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1

Policy iteration based on a learned transition model  

Science Conference Proceedings (OSTI)

This paper investigates a reinforcement learning method that combines learning a model of the environment with least-squares policy iteration (LSPI). The LSPI algorithm learns a linear approximation of the optimal state-action value function; the idea ...

Vivek Ramavajjala; Charles Elkan

2012-09-01T23:59:59.000Z

2

STELLOPT Modeling of the 3D Diagnostic Response in ITER  

SciTech Connect

The ITER three dimensional diagnostic response to an n=3 resonant magnetic perturbation is modeled using the STELLOPT code. The in-vessel coils apply a resonant magnetic perturbation (RMP) fi eld which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20 % changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 cm shifts on the low field side of the plasma. This suggests that the ITER diagnostic will be able to diagnose the 3D structure of the equilibria.

Lazerson, Samuel A

2013-05-07T23:59:59.000Z

3

A hierarchical fracture model for the iterative multiscale finite volume method  

Science Conference Proceedings (OSTI)

An iterative multiscale finite volume (i-MSFV) method is devised for the simulation of multiphase flow in fractured porous media in the context of a hierarchical fracture modeling framework. Motivated by the small pressure change inside highly conductive ... Keywords: Fractured porous media, Hierarchical fractured modeling, Iterative multiscale finite volume, Iterative multiscale methods, Multiscale finite volume, Multiscale fracture modeling, Multiscale methods

Hadi Hajibeygi; Dimitris Karvounis; Patrick Jenny

2011-10-01T23:59:59.000Z

4

Iterated Function System Models in Data Analysis: Detection and Separation  

E-Print Network (OSTI)

We investigate the use of iterated function system (IFS) models for data analysis. An IFS is a discrete dynamical system in which each time step corresponds to the application of one of a finite collection of maps. The maps, which represent distinct dynamical regimes, may act in some pre-determined sequence or may be applied in random order. An algorithm is developed to detect the sequence of regime switches under the assumption of continuity. This method is tested on a simple IFS and applied to an experimental computer performance data set. This methodology has a wide range of potential uses: from change-point detection in time-series data to the field of digital communications.

Zachary Alexander; Elizabeth Bradley; Joshua Garland; James D. Meiss

2011-08-15T23:59:59.000Z

5

An Iterative Method for the Construction of Equilibrium N-Body Models for Stellar Disks  

E-Print Network (OSTI)

One widely used technique for the construction of equilibrium models of stellar disks is based on the Jeans equations and the moments of velocity distribution functions derived using these equations. Stellar disks constructed using this technique are shown to be "not entirely" in equilibrium. Our attempt to abandon the epicyclic approximation and the approximation of infinite isothermal layers, which are commonly adopted in this technique, failed to improve the situation substantially. We conclude that the main drawback of techniques based on the Jeans equations is that the system of equations employed is not closed, and therefore requires adopting an essentially ad hoc additional closure condition. A new iterative approach to constructing equilibrium N-body models with a given density distribution is proposed. The main idea behind this approach is that a model is first constructed using some approximation method, and is then allowed to adjust to an equilibrium state with the specified density and the required parameters of the velocity distribution remaining fixed in the process. This iterative approach was used to construct isotropic, spherically symmetric models and models of stellar disks embedded in an external potential. The numerical models constructed prove to be close to equilibrium. It is shown that the commonly adopted assumption that the profile of the radial velocity dispersion is exponential may be wrong. The technique proposed can be applied to a wide range of problems involving the construction of models of stellar systems with various geometries.

S. A. Rodionov; N. Ya. Sotnikova

2006-11-06T23:59:59.000Z

6

An iterative stochastic ensemble method for parameter estimation of subsurface flow models  

Science Conference Proceedings (OSTI)

Parameter estimation for subsurface flow models is an essential step for maximizing the value of numerical simulations for future prediction and the development of effective control strategies. We propose the iterative stochastic ensemble method (ISEM) ... Keywords: Iterative stochastic ensemble method, Parameter estimation, Regularization, Subsurface flow models

Ahmed H. Elsheikh, Mary F. Wheeler, Ibrahim Hoteit

2013-06-01T23:59:59.000Z

7

An Iterative Regression Model for Estimating Soybean Yields from Environmental Data  

Science Conference Proceedings (OSTI)

A model was developed for using weather data, to estimate the yields of soybeans for varieties adapted to the central United States. The model utilized an iterative regression analysis for relating soybean yields to environmental variables. This ...

Andres C. Ravelo; Wayne L. Decker

1981-11-01T23:59:59.000Z

8

Experiment and Modeling of ITER Demonstration Discharges in the DIII-D Tokamak  

Science Conference Proceedings (OSTI)

DIII-D is providing experimental evaluation of 4 leading ITER operational scenarios: the baseline scenario in ELMing H-mode, the advanced inductive scenario, the hybrid scenario, and the steady state scenario. The anticipated ITER shape, aspect ratio and value of I/{alpha}B were reproduced, with the size reduced by a factor of 3.7, while matching key performance targets for {beta}{sub N} and H{sub 98}. Since 2008, substantial experimental progress was made to improve the match to other expected ITER parameters for the baseline scenario. A lower density baseline discharge was developed with improved stationarity and density control to match the expected ITER edge pedestal collisionality ({nu}*{sub e} {approx} 0.1). Target values for {beta}{sub N} and H{sub 98} were maintained at lower collisionality (lower density) operation without loss in fusion performance but with significant change in ELM characteristics. The effects of lower plasma rotation were investigated by adding counter-neutral beam power, resulting in only a modest reduction in confinement. Robust preemptive stabilization of 2/1 NTMs was demonstrated for the first time using ECCD under ITER-like conditions. Data from these experiments were used extensively to test and develop theory and modeling for realistic ITER projection and for further development of its optimum scenarios in DIII-D. Theory-based modeling of core transport (TGLF) with an edge pedestal boundary condition provided by the EPED1 model reproduces T{sub e} and T{sub i} profiles reasonably well for the 4 ITER scenarios developed in DIII-D. Modeling of the baseline scenario for low and high rotation discharges indicates that a modest performance increase of {approx} 15% is needed to compensate for the expected lower rotation of ITER. Modeling of the steady-state scenario reproduces a strong dependence of confinement, stability, and noninductive fraction (f{sub NI}) on q{sub 95}, as found in the experimental I{sub p} scan, indicating that optimization of the q profile is critical to simultaneously achieving the f{sub NI} = 1 and Q = 5 goals. Extended integrated modeling is being developed to improve capability for ITER projection by including the experimental observations of density peaking, ELM characteristics, NTM suppression and coupled core-edge-SOL transport.

Park, Jin Myung [ORNL; Doyle, E. J. [University of California, Los Angeles; Ferron, J.R. [General Atomics, San Diego; Holcomb, C T [Lawrence Livermore National Laboratory (LLNL); Jackson, G. L. [General Atomics; Lao, L. L. [General Atomics; Luce, T.C. [General Atomics, San Diego; Owen, Larry W [ORNL; Murakami, Masanori [ORNL; Osborne, T. H. [General Atomics; Politzer, P. A. [General Atomics, San Diego; Prater, R. [General Atomics; Snyder, P. B. [General Atomics

2011-01-01T23:59:59.000Z

9

Weight optimisation for iterative distributed model predictive control applied to power networks  

Science Conference Proceedings (OSTI)

This paper presents a weight tuning technique for iterative distributed Model Predictive Control (MPC). Particle Swarm Optimisation (PSO) is used to optimise both the weights associated with disturbance rejection and those associated with achieving consensus ... Keywords: Distributed model predictive control, Multi-agent, Particle swarm optimisation, Power networks, Smart grids, Weight tuning

Paul Mc Namara; Rudy R. Negenborn; Bart De Schutter; Gordon Lightbody

2013-01-01T23:59:59.000Z

10

Testing and modeling of diffusion bonded prototype optical windows under ITER conditions  

SciTech Connect

Glass-metal joints are a part of ITER optical diagnostics windows. These joints must be leak tight for the safety (presence of tritium in ITER) and to preserve the vacuum. They must also withstand the ITER environment: temperatures up to 220 deg.C and fast neutron fluxes of {approx}3.10{sup 9} n/cm{sup 2}.s. At the moment, little information is available about glass-metal joints suitable for ITER. Therefore, we performed mechanical and thermal tests on some prototypes of an aluminium diffusion bonded optical window. Finite element modeling with Abaqus code was used to understand the experimental results. The prototypes were helium leaking probably due to very tiny cracks in the interaction layer between the steel and the aluminium. However, they were all able to withstand a thermal cycling test up to 200 deg. C; no damage could be seen after the tests by visual inspection. The prototypes successfully passed push-out test with a 500 N load. During the destructive push-out tests the prototypes broke at a 6-12 kN load between the aluminium layer and the steel or the glass, depending on the surface quality of the glass. The microanalysis of the joints has also been performed. The finite element modeling of the push-out tests is in a reasonable agreement with the experiments. According to the model, the highest thermal stress is created in the aluminium layer. Thus, the aluminium joint seems to be the weakest part of the prototypes. If this layer is improved, it will probably make the prototype helium leak tight and as such, a good ITER window candidate. (authors)

Jacobs, M. [Flemish Inst. for Technological Research, Mol (Belgium); Van Oost, G. [Dept. of Applied Physics, Ghent Univ., Ghent (Belgium); Degrieck, J.; De Baere, I. [Dept. of Materials Science and Engineering, Ghent Univ., Ghent (Belgium); Gusarov, A. [Belgian Nuclear Research Center, Mol (Belgium); Gubbels, F. [TNO, Eindhoven (Netherlands); Massaut, V. [Belgian Nuclear Research Center, Mol (Belgium)

2011-07-01T23:59:59.000Z

11

The Effect of Process Topology and Load Balancing on Parallel Programming Models for SMP Clusters and Iterative Algorithms  

Science Conference Proceedings (OSTI)

This article focuses on the effect of both process topology and load balancing on various programming models for SMP clusters and iterative algorithms. More specifically, we consider nested loop algorithms with constant flow dependencies, that can be ... Keywords: MPI, OpenMP, SMP clusters, high performance computing, hybrid programming, iterative algorithms, parallel programming, tiling

Nikolaos Drosinos; Nectarios Koziris

2006-01-01T23:59:59.000Z

12

BAKTRAK: Backtracking drifting objects using an iterative algorithm with a forward trajectory model  

E-Print Network (OSTI)

The task of determining the origin of a drifting object after it has been located is highly complex due to the uncertainties in drift properties and environmental forcing (wind, waves and surface currents). Usually the origin is inferred by running a trajectory model (stochastic or deterministic) in reverse. However, this approach has some severe drawbacks, most notably the fact that many drifting objects go through nonlinear state changes underway (e.g., evaporating oil or a capsizing lifeboat). This makes it difficult to naively construct a reverse-time trajectory model which realistically predicts the earliest possible time the object may have started drifting. We propose instead a different approach where the original (forward) trajectory model is kept unaltered while an iterative seeding and selection process allows us to retain only those particles that end up within a certain time-space radius of the observation. An iterative refinement process named BAKTRAK is employed where those trajectories that do...

Breivik, Øyvind; Ommundsen, Atle; Wettre, Cecilie

2011-01-01T23:59:59.000Z

13

Generalized Iterative Annealing Model for the action of RNA chaperones  

E-Print Network (OSTI)

As a consequence of the rugged landscape of RNA molecules their folding is described by the kinetic partitioning mechanism according to which only a small fraction ($\\phi_F$) reaches the folded state while the remaining fraction of molecules is kinetically trapped in misfolded intermediates. The transition from the misfolded states to the native state can far exceed biologically relevant time. Thus, RNA folding in vivo is often aided by protein cofactors, called RNA chaperones, that can rescue RNAs from a multitude of misfolded structures. We consider two models, based on chemical kinetics and chemical master equation, for describing assisted folding. In the passive model, applicable for class I substrates, transient interactions of misfolded structures with RNA chaperones alone are sufficient to destabilize the misfolded structures, thus entropically lowering the barrier to folding. For this mechanism to be efficient the intermediate ribonucleoprotein (RNP) complex between collapsed RNA and protein cofactor ...

Hyeon, Changbong

2013-01-01T23:59:59.000Z

14

Generalized Iterative Annealing Model for the action of RNA chaperones  

E-Print Network (OSTI)

As a consequence of the rugged landscape of RNA molecules their folding is described by the kinetic partitioning mechanism according to which only a small fraction ($\\phi_F$) reaches the folded state while the remaining fraction of molecules is kinetically trapped in misfolded intermediates. The transition from the misfolded states to the native state can far exceed biologically relevant time. Thus, RNA folding in vivo is often aided by protein cofactors, called RNA chaperones, that can rescue RNAs from a multitude of misfolded structures. We consider two models, based on chemical kinetics and chemical master equation, for describing assisted folding. In the passive model, applicable for class I substrates, transient interactions of misfolded structures with RNA chaperones alone are sufficient to destabilize the misfolded structures, thus entropically lowering the barrier to folding. For this mechanism to be efficient the intermediate ribonucleoprotein (RNP) complex between collapsed RNA and protein cofactor should have optimal stability. We also introduce an active model (suitable for stringent substrates with small $\\phi_F$), which accounts for the recent experimental findings on the action of CYT-19 on the group I intron ribozyme, showing that RNA chaperones does not discriminate between the misfolded and the native states. In the active model, the RNA chaperone system utilizes chemical energy of ATP hydrolysis to repeatedly bind and release misfolded and folded RNAs, resulting in substantial increase of yield of the native state. The theory outlined here shows, in accord with experiments, that in the steady state the native state does not form with unit probability.

Changbong Hyeon; D. Thirumalai

2013-06-17T23:59:59.000Z

15

Cryogenic Viscous Compressor Development and Modeling for the ITER Vacuum System  

SciTech Connect

The ITER vacuum system requires a roughing pump system that can pump the exhaust gas from the torus cryopumps to the tritium exhaust processing plant. The gas will have a high tritium content and therefore conventional vacuum pumps are not suitable. A pump called a cryogenic viscous compressor (CVC) is being designed for the roughing system to pump from ~500 Pa to 10 Pa at flow rates of 200 Pa-m3/ s. A unique feature of this pump is that is allows any helium in the gas to flow through the pump where it is sent to the detritiation system before exhausting to atmosphere. A small scale prototype of the CVC is being tested for heat transfer characteristics and compared to modeling results to ensure reliable operation of the full scale CVC. Keywords- ITER; vacuum; fuel cycle

Baylor, Larry R [ORNL; Meitner, Steven J [ORNL; Barbier, Charlotte N [ORNL; Combs, Stephen Kirk [ORNL; Duckworth, Robert C [ORNL; Edgemon, Timothy D [ORNL; Rasmussen, David A [ORNL; Hechler, Michael P [ORNL; Kersevan, R. [ITER Organization, Cadarache, France; Dremel, M. [General Atomics, San Diego; Pearce, R.J.H. [General Atomics, San Diego; Boissin, Jean Claude [Consultant

2011-01-01T23:59:59.000Z

16

Coupling characteristics of the ITER relevant lower hybrid antenna in Tore Supra: experiments and modelling  

Science Conference Proceedings (OSTI)

A new concept of lower hybrid antenna for current drive has been proposed for ITER [Bibet et al, Nuclear Fusion 1995]: the Passive Active Multijunction (PAM) antenna that relies on a periodic combination of active and passive waveguides. An actively cooled PAM antenna at 3.7 GHz has been recently installed on the tokamak Tore Supra. The paper summarizes the comprehensive experimental characterization of the linear coupling properties of the PAM antenna to the Tore Supra plasmas. These experimental results are systematically compared with the linear wave coupling theory via the linear ALOHA code. Good agreement between experimental results and ALOHA have been obtained. The detailed validation of the coupling modelling is an important step toward the validation of the PAM concept in view of further optimizing the electromagnetic properties of the future ITER antenna.

Preynas, M.; Ekedahl, A.; Fedorczak, N.; Goniche, M.; Guilhem, D.; Gunn, J. P.; Hillairet, J.; Litaudon, X. [CEA, IRFM, 13108 Saint Paul lez Durance (France); Associacao Euratom-IST, Centro de Fusao Nuclear 1049-001 Lisboa (Portugal)

2011-12-23T23:59:59.000Z

17

A fast iterative model for discrete velocity calculations on triangular grids  

SciTech Connect

A fast synthetic type iterative model is proposed to speed up the slow convergence of discrete velocity algorithms for solving linear kinetic equations on triangular lattices. The efficiency of the scheme is verified both theoretically by a discrete Fourier stability analysis and computationally by solving a rarefied gas flow problem. The stability analysis of the discrete kinetic equations yields the spectral radius of the typical and the proposed iterative algorithms and reveal the drastically improved performance of the latter one for any grid resolution. This is the first time that stability analysis of the full discrete kinetic equations related to rarefied gas theory is formulated, providing the detailed dependency of the iteration scheme on the discretization parameters in the phase space. The corresponding characteristics of the model deduced by solving numerically the rarefied gas flow through a duct with triangular cross section are in complete agreement with the theoretical findings. The proposed approach may open a way for fast computation of rarefied gas flows on complex geometries in the whole range of gas rarefaction including the hydrodynamic regime.

Szalmas, Lajos [Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334 (Greece); Valougeorgis, Dimitris [Department of Mechanical Engineering, University of Thessaly, Pedion Areos, Volos 38334 (Greece)], E-mail: diva@mie.uth.gr

2010-06-01T23:59:59.000Z

18

The impact of parallel programming models on the performance of iterative linear solvers for finite element applications  

Science Conference Proceedings (OSTI)

Parallel iterative linear solvers for unstructured grids in FEM applications, originally developed for the Earth Simulator (ES), are ported to various types of parallel computer. The performance of flat MPI and hybrid parallel programming models is compared ...

Kengo Nakajima

2006-06-01T23:59:59.000Z

19

ElementNodeIterator  

Science Conference Proceedings (OSTI)

... iter=element->node_iterator(); !iter.end(); ++iter) { Node *node = iter.node(); // do something ... node returns a pointer to the iterator's current Node . ...

2013-08-23T23:59:59.000Z

20

An Iterative Method for Constructing Equilibrium Phase Models of Stellar Systems  

E-Print Network (OSTI)

We present a new method for constructing equilibrium phase models for stellar systems, which we call the iterative method. It relies on constrained, or guided evolution, so that the equilibrium solution has a number of desired parameters and/or constraints. This method is very powerful, to a large extent due to its simplicity. It can be used for mass distributions with an arbitrary geometry and a large variety of kinematical constraints. We present several examples illustrating it. Applications of this method include the creation of initial conditions for N-body simulations and the modelling of galaxies from their photometric and kinematic observations.

S. A. Rodionov; E. Athanassoula; N. Ya Sotnikova

2008-08-14T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

ITER Model Coil Tests Overview: Nb3Sn Strand Properties in Cable-in-Conduit-Conductors  

SciTech Connect

During the ITER Model Coil Program two large coils and three Insert coils were built and tested. The test campaigns provided very valuable data on the Conductor in Conduit Cable (CICC) properties. The tests showed that the Nb3Sn strands in CICC behave differently than so-called witness strands, which underwent the same heat treatment. The paper describes Volt-temperature characteristics (VTC) and Volt-Ampere characteristics (VAC) measured in the tests, presents comparisons with the witness strands, and interprets the test results.

Martovetsky, N N

2003-04-14T23:59:59.000Z

22

Integrated modelling of steady-state scenarios and heating and current drive mixes for ITER  

Science Conference Proceedings (OSTI)

Recent progress on ITER steady-state (SS) scenario modelling by the ITPA-IOS group is reviewed. Code-to-code benchmarks as the IOS group's common activities for the two SS scenarios (weak shear scenario and internal transport barrier scenario) are discussed in terms of transport, kinetic profiles, and heating and current drive (CD) sources using various transport codes. Weak magnetic shear scenarios integrate the plasma core and edge by combining a theory-based transport model (GLF23) with scaled experimental boundary profiles. The edge profiles (at normalized radius rho = 0.8-1.0) are adopted from an edge-localized mode-averaged analysis of a DIII-D ITER demonstration discharge. A fully noninductive SS scenario is achieved with fusion gain Q = 4.3, noninductive fraction f(NI) = 100%, bootstrap current fraction f(BS) = 63% and normalized beta beta(N) = 2.7 at plasma current I(p) = 8MA and toroidal field B(T) = 5.3 T using ITER day-1 heating and CD capability. Substantial uncertainties come from outside the radius of setting the boundary conditions (rho = 0.8). The present simulation assumed that beta(N)(rho) at the top of the pedestal (rho = 0.91) is about 25% above the peeling-ballooning threshold. ITER will have a challenge to achieve the boundary, considering different operating conditions (T(e)/T(i) approximate to 1 and density peaking). Overall, the experimentally scaled edge is an optimistic side of the prediction. A number of SS scenarios with different heating and CD mixes in a wide range of conditions were explored by exploiting the weak-shear steady-state solution procedure with the GLF23 transport model and the scaled experimental edge. The results are also presented in the operation space for DT neutron power versus stationary burn pulse duration with assumed poloidal flux availability at the beginning of stationary burn, indicating that the long pulse operation goal (3000s) at I(p) = 9 MA is possible. Source calculations in these simulations have been revised for electron cyclotron current drive including parallel momentum conservation effects and for neutral beam current drive with finite orbit and magnetic pitch effects.

Murakami, Masanori [ORNL; Park, Jin Myung [ORNL

2011-01-01T23:59:59.000Z

23

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Emilian Popov; Alice Ying

24

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System  

SciTech Connect

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and to provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.

Ying, Alice [University of California, Los Angeles; Popov, Emilian L [ORNL

2011-01-01T23:59:59.000Z

25

CFD MODELING OF ITER CABLE-IN-CONDUIT SUPERCONDUCTORS. PART V: COMBINED MOMENTUM AND HEAT TRANSFER IN RIB ROUGHENED PIPES  

Science Conference Proceedings (OSTI)

Computational Fluid Dynamics (CFD) techniques have been proposed and applied in a series of papers to analyze cable-in-conduit conductors (CICC) for the International Thermonuclear Experimental Reactor (ITER). Previous work on the pressure drop in the central channel of ITER CICC is extended here to the problem of combined heat and momentum transfer. The CFD model, solved by the FLUENT commercial code, is first validated against 2D and 3D data from compact heat exchangers, showing good agreement. The Colburn analogy between the friction factor f and the Nusselt number Nu is not verified in the considered 2D geometries, as shown by both experiment and simulation. The validated CFD model is finally applied to the 3D analysis of central channel-like geometries relevant for ITER CICC. It is shown that the heat transfer coefficient on the central channel side stays relatively close to the smooth-pipe (Dittus-Boelter) value.

Zanino, R.; Giors, S. [Dipartimento di Energetica, Politecnico Torino, I-10129 (Italy)

2008-03-16T23:59:59.000Z

26

Modeling of the ITER-like wide-angle infrared thermography view of JET  

SciTech Connect

Infrared (IR) thermography systems are mandatory to ensure safe plasma operation in fusion devices. However, IR measurements are made much more complicated in metallic environment because of the spurious contributions of the reflected fluxes. This paper presents a full predictive photonic simulation able to assess accurately the surface temperature measurement with classical IR thermography from a given plasma scenario and by taking into account the optical properties of PFCs materials. This simulation has been carried out the ITER-like wide angle infrared camera view of JET in comparing with experimental data. The consequences and the effects of the low emissivity and the bidirectional reflectivity distribution function used in the model for the metallic PFCs on the contribution of the reflected flux in the analysis are discussed.

Aumeunier, M.-H. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); OPTIS, ZE de La Farlede, F-83078 Toulon Cedex 9 (France); Firdaouss, M.; Travere, J.-M.; Loarer, T.; Gauthier, E.; Martin, V. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Chabaud, D.; Humbert, E. [OPTIS, ZE de La Farlede, F-83078 Toulon Cedex 9 (France); Collaboration: JET-EFDA Contributors

2012-10-15T23:59:59.000Z

27

NLTE model calculations for the solar atmosphere with an iterative treatment of opacity distribution functions  

E-Print Network (OSTI)

Modeling the variability of the solar spectral irradiance is a key factor for understanding the solar influence on the climate of the Earth. As a first step to calculating the solar spectral irradiance variations we reproduce the solar spectrum for the quiet Sun over a broad wavelength range with an emphasis on the UV. We introduce the radiative transfer code COSI which calculates solar synthetic spectra under conditions of non-local thermodynamic equilibrium (NLTE). A self-consistent simultaneous solution of the radiative transfer and the statistical equation for the level populations guarantees that the correct physics is considered for wavelength regions where the assumption of local thermodynamic equilibrium (LTE) breaks down. The new concept of iterated opacity distribution functions (NLTE-ODFs), through which all line opacities are included in the NLTE radiative transfer calculation, is presented. We show that it is essential to include the line opacities in the radiative transfer to reproduce the solar...

Haberreiter, M; Hubeny, I

2008-01-01T23:59:59.000Z

28

Interruptible iterators  

E-Print Network (OSTI)

This paper introduces interruptible iterators, a language feature that makes expressive iteration abstractions much easier to implement. Iteration abstractions are valuable for software design, as shown by their frequent use in well-designed data structure libraries such as the Java Collections Framework. While Java iterators support iteration abstraction well from the standpoint of client code, they are awkward to implement correctly and efficiently, especially if the iterator needs to support imperative update of the underlying collection, such as removing the current element. Some languages, such as CLU and C # 2.0, support iteration through a limited coroutine mechanism, but these mechanisms do not support imperative updates. Interruptible iterators are more powerful coroutines in which the loop body is able to interrupt the iterator with requests to perform updates. Interrupts are similar to exceptions, but propagate differently and have resumption semantics. Interruptible iterators have been implemented as part of the JMatch programming language, an extended version of Java. A JMatch reimplementation of the Java Collections Framework shows that implementations can be made substantially shorter and simpler; performance results show that this language mechanism can also be implemented efficiently.

Jed Liu; Aaron Kimball; Andrew C. Myers

2006-01-01T23:59:59.000Z

29

Accelerated Iterative Method for Solving Steady Problems of Linearized Atmospheric Models  

Science Conference Proceedings (OSTI)

A new approach, referred to as the accelerated iterative method (AIM), is developed for obtaining steady atmospheric responses with a zonally varying basic state. The linear dynamical operator is divided into two parts, one associated with the ...

Masahiro Watanabe; Fei-fei Jin; Lin Pan

2006-12-01T23:59:59.000Z

30

An Iterative Aggregation/Disaggregation Approach for the Solution of a Mixed Integer Nonlinear Oilfield Infrastructure Planning Model  

E-Print Network (OSTI)

A multiperiod MINLP model for offshore oilfield infrastructure planning is presented where nonlinear reservoir behavior is incorporated directly into the formulation. Discrete decisions include the selection of production platforms, well platforms and wells to be installed/drilled, as well as the drilling schedule for the wells over the planning horizon. Continuous decisions include the capacities of the platforms, as well as the production profile for each well in each time period. For the solution of this model, an iterative aggregation/disaggregation algorithm is proposed in which logic-based methods, a bilevel decomposition technique, the use of convex envelopes and aggregation of time periods are integrated. Furthermore, a novel dynamic programming sub-problem is proposed to improve the aggregation scheme at each iteration in order to obtain an aggregate problem that resembles the disaggregate problem more closely. A number of examples are presented to illustrate the performance of the proposed method. Keywords Oilfield planning, MINLP, aggregation, decomposition

Susara A. Van Den Heever; Ignacio Grossmann

1999-01-01T23:59:59.000Z

31

Implementation of the Iterative Proportion Fitting Algorithm for Geostatistical Facies Modeling  

SciTech Connect

In geostatistics, most stochastic algorithm for simulation of categorical variables such as facies or rock types require a conditional probability distribution. The multivariate probability distribution of all the grouped locations including the unsampled location permits calculation of the conditional probability directly based on its definition. In this article, the iterative proportion fitting (IPF) algorithm is implemented to infer this multivariate probability. Using the IPF algorithm, the multivariate probability is obtained by iterative modification to an initial estimated multivariate probability using lower order bivariate probabilities as constraints. The imposed bivariate marginal probabilities are inferred from profiles along drill holes or wells. In the IPF process, a sparse matrix is used to calculate the marginal probabilities from the multivariate probability, which makes the iterative fitting more tractable and practical. This algorithm can be extended to higher order marginal probability constraints as used in multiple point statistics. The theoretical framework is developed and illustrated with estimation and simulation example.

Li Yupeng, E-mail: yupeng@ualberta.ca; Deutsch, Clayton V. [University of Alberta (Canada)

2012-06-15T23:59:59.000Z

32

An iterative approach to build relevant ontology-aware data-driven models  

Science Conference Proceedings (OSTI)

In many fields involving complex environments or living organisms, data-driven models are useful to make simulations in order to extrapolate costly experiments and to design decision-support tools. Learning methods can be used to build interpretable ... Keywords: Classification tree, Expert knowledge, Knowledge integration, Machine learning, Ontology

Rallou Thomopoulos; SéBastien Destercke; Brigitte Charnomordic; Iyan Johnson; JoëL AbéCassis

2013-02-01T23:59:59.000Z

33

Buried Waste Integrated Demonstration stakeholder involvement model  

Science Conference Proceedings (OSTI)

The Buried Waste Integrated Demonstration (BWID) is a program funded by the US Department of Energy (DOE) Office of Technology Development. BWID supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that together form a comprehensive remediation system for the effective and efficient remediation of buried waste. Stakeholder participation in the DOE Environmental Management decision-making process is critical to remediation efforts. Appropriate mechanisms for communication with the public, private sector, regulators, elected officials, and others are being aggressively pursued by BWID to permit informed participation. This document summarizes public outreach efforts during FY-93 and presents a strategy for expanded stakeholder involvement during FY-94.

Kaupanger, R.M.; Kostelnik, K.M.; Milam, L.M.

1994-04-01T23:59:59.000Z

34

Iterative Time Reversal with Tunable Convergence  

E-Print Network (OSTI)

We propose and test an iterative technique for improving the temporal focusing of a time reversal mirror. A single amplification parameter is introduced to tune the convergence of the iteration. The tunable iterative technique is validated by tests on an experimental electromagnetic time reversal mirror, as well as on a novel numerical model.

Biniyam Tesfaye Taddese; Thomas M. Antonsen; Edward Ott; Steven M. Anlage

2011-07-07T23:59:59.000Z

35

Testing alternative models of individuals' social media involvement and satisfaction  

Science Conference Proceedings (OSTI)

This study extends the Technology Acceptance Model 3 (TAM 3) within the context of the rapidly evolving area of social media. Since social media requires the user's active participation and processing of information as well as the creation of user-generated ... Keywords: Involvement, Social media sites, Social media usage intention, TAM 3, Three alternative models, User satisfaction

Jeen-Su Lim, Abdulrahman Al-Aali, John H. Heinrichs, Kee-Sook Lim

2013-11-01T23:59:59.000Z

36

The Iterate Manual  

E-Print Network (OSTI)

This is the manual for version 1.1 of Iterate, a powerful iteration macro for Common Lisp. Iterate is similar to Loop but provides numerous additional features, is well integrated with Lisp, and is extensible.

Amsterdam, Jonathan

1990-10-01T23:59:59.000Z

37

An approach to iterative learning control for spatio-temporal dynamics using nD discrete linear systems models  

Science Conference Proceedings (OSTI)

Iterative Learning Control (ILC) is now well established in terms of both the underlying theory and experimental application. This approach is specifically targeted at cases where the same operation is repeated over a finite duration with resetting between ... Keywords: Explicit discretization, Iterative learning control, PDEs, nD linear systems

B?a?ej Cichy; Krzysztof Ga?kowski; Eric Rogers; Anton Kummert

2011-03-01T23:59:59.000Z

38

Analysis of Spontaneous Mass Generation by Iterative Method in the Nambu-Jona-Lasinio Model and Gauge Theories  

E-Print Network (OSTI)

We propose a new iterative method to directly calculate the spontaneous mass generation due to the dynamical chiral symmetry breaking. We can conclude the physical mass definitely without recourse to any other consideration like the free energy comparison.

Ken-Ichi Aoki; Shinnosuke Onai; Daisuke Sato

2013-04-10T23:59:59.000Z

39

A fuzzy clustering iterative model using chaotic differential evolution algorithm for evaluating flood disaster  

Science Conference Proceedings (OSTI)

Flood disaster is a kind of frequent natural hazards. The objective of flood disaster evaluation is to establish hazard assessment model for managing flood and preventing disaster. Base on the chaotic optimization theory, this paper proposes a chaotic ... Keywords: Chaotic map, Differential evolution algorithm, Evolutionary computation, Flood disaster evaluation, Fuzzy clustering

Yaoyao He; Jianzhong Zhou; Pangao Kou; Ning Lu; Qiang Zou

2011-08-01T23:59:59.000Z

40

US ITER | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

US ITER Working with US ITER An unprecedented collaboration The international ITER fusion facility is now under construction in Cadarache, France Home | Science & Discovery | US...

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Iterative Methods for Neutron Transport Eigenvalue Problems  

Science Conference Proceedings (OSTI)

We discuss iterative methods for computing criticality in nuclear reactors. In general this requires the solution of a generalized eigenvalue problem for an unsymmetric integro-differential operator in six independent variables, modeling transport, scattering, ... Keywords: criticality, generalized eigenvalue problem, inexact inverse iteration, neutron transport, symmetry

Fynn Scheben; Ivan G. Graham

2011-09-01T23:59:59.000Z

42

Specifying java iterators with JML and Esc/Java2  

Science Conference Proceedings (OSTI)

The 2006 SAVCBS Workshop has posed a Challenge Problem on the topic of specifying iterators. This note provides a specification in the Java Modeling Language (JML) [1, 2] for the Java interfaces Iterator and Iterable that captures the interactions ... Keywords: ESC/Java2, JML, specification, static analysis, verification

David R. Cok

2006-11-01T23:59:59.000Z

43

On the progressive iteration approximation property and alternative iterations  

Science Conference Proceedings (OSTI)

This note revisits the progressive iteration approximation property and some recent modifications from the point of view of iterative methods for solving linear systems. In particular we show the connection with the classical Richardson iteration and ... Keywords: GMRES, Interpolation, Iterative methods, Progressive iteration approximation

J. M. Carnicer; J. Delgado; J. M. Peña

2011-12-01T23:59:59.000Z

44

Iterative phase estimation  

E-Print Network (OSTI)

We give an iterative algorithm for phase estimation of a parameter theta, which is within a logarithmic factor of the Heisenberg limit. Unlike other methods, we do not need any entanglement or an extra rotation gate which can perform arbitrary rotations with almost perfect accuracy: only a single copy of the unitary channel and basic measurements are needed. Simulations show that the algorithm is successful. We also look at iterative phase estimation when depolarizing noise is present. It is seen that the algorithm is still successful provided the number of iterative stages is below a certain threshold.

Caleb J O'Loan

2009-04-22T23:59:59.000Z

45

Final Report on ITER Task Agreement 81-08  

Science Conference Proceedings (OSTI)

As part of an ITER Implementing Task Agreement (ITA) between the ITER US Participant Team (PT) and the ITER International Team (IT), the INL Fusion Safety Program was tasked to provide the ITER IT with upgrades to the fusion version of the MELCOR 1.8.5 code including a beryllium dust oxidation model. The purpose of this model is to allow the ITER IT to investigate hydrogen production from beryllium dust layers on hot surfaces inside the ITER vacuum vessel (VV) during in-vessel loss-of-cooling accidents (LOCAs). Also included in the ITER ITA was a task to construct a RELAP5/ATHENA model of the ITER divertor cooling loop to model the draining of the loop during a large ex-vessel pipe break followed by an in-vessel divertor break and compare the results to a simular MELCOR model developed by the ITER IT. This report, which is the final report for this agreement, documents the completion of the work scope under this ITER TA, designated as TA 81-08.

Richard L. Moore

2008-03-01T23:59:59.000Z

46

What is ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

* Assumes 40% efficiency in the conversion of heat to electricity. Modern electric power plant*. 500 Million Watts 2,500 Million Watts 1975 1980 1995 ITER Demo PROGRESS IN...

47

Iterated multidimensional wave conversion  

Science Conference Proceedings (OSTI)

Mode conversion can occur repeatedly in a two-dimensional cavity (e.g., the poloidal cross section of an axisymmetric tokamak). We report on two novel concepts that allow for a complete and global visualization of the ray evolution under iterated conversions. First, iterated conversion is discussed in terms of ray-induced maps from the two-dimensional conversion surface to itself (which can be visualized in terms of three-dimensional rooms). Second, the two-dimensional conversion surface is shown to possess a symplectic structure derived from Dirac constraints associated with the two dispersion surfaces of the interacting waves.

Brizard, A. J. [Dept. Physics, Saint Michael's College, Colchester, VT 05439 (United States); Tracy, E. R.; Johnston, D. [Dept. Physics, College of William and Mary, Williamsburg, VA 23187-8795 (United States); Kaufman, A. N. [LBNL and Physics Dept., UC Berkeley, Berkeley, CA 94720 (United States); Richardson, A. S. [T-5, LANL, Los Alamos, NM 87545 (United States); Zobin, N. [Dept. Mathematics, College of William and Mary, Williamsburg, VA 23187-8795 (United States)

2011-12-23T23:59:59.000Z

48

The ITER Project: International Collaboration to Demonstrate...  

NLE Websites -- All DOE Office Websites (Extended Search)

ITER Project: International Collaboration to Demonstrate Nuclear Fusion American Fusion News Category: U.S. ITER Link: The ITER Project: International Collaboration to Demonstrate...

49

Work stealing and persistence-based load balancers for iterative overdecomposed applications  

Science Conference Proceedings (OSTI)

Applications often involve iterative execution of identical or slowly evolving calculations. Such applications require incremental rebalancing to improve load balance across iterations. In this paper, we consider the design and evaluation of two distinct ... Keywords: dynamic load balancing, hierarchical load balancer, iterative applications, persistence, task scheduling, work stealing

Jonathan Lifflander; Sriram Krishnamoorthy; Laxmikant V. Kale

2012-06-01T23:59:59.000Z

50

Iterations of nonlinear entanglement witnesses  

E-Print Network (OSTI)

We describe a generic way to improve a given linear entanglement witness by a quadratic, nonlinear term. This method can be iterated, leading to a whole sequence of nonlinear witnesses, which become stronger in each step of the iteration. We show how to optimize this iteration with respect to a given state, and prove that in the limit of the iteration the nonlinear witness detects all states that can be detected by the positive map corresponding to the original linear witness.

Tobias Moroder; Otfried Gühne; Norbert Lütkenhaus

2008-06-04T23:59:59.000Z

51

Don't Loop, Iterate  

E-Print Network (OSTI)

I describe an iteration macro for Common Lisp that is clear, efficient, extensible, and in excellent taste.

Amsterdam, Jonathan

52

The physics role of ITER  

SciTech Connect

Experimental research on the International Thermonuclear Experimental Reactor (ITER) will go far beyond what is possible on present-day tokamaks to address new and challenging issues in the physics of reactor-like plasmas. First and foremost, experiments in ITER will explore the physics issues of burning plasmas--plasmas that are dominantly self-heated by alpha-particles created by the fusion reactions themselves. Such issues will include (i) new plasma-physical effects introduced by the presence within the plasma of an intense population of energetic alpha particles; (ii) the physics of magnetic confinement for a burning plasma, which will involve a complex interplay of transport, stability and an internal self-generated heat source; and (iii) the physics of very-long-pulse/steady-state burning plasmas, in which much of the plasma current is also self-generated and which will require effective control of plasma purity and plasma-wall interactions. Achieving and sustaining burning plasma regimes in a tokamak necessarily requires plasmas that are larger than those in present experiments and have higher energy content and power flow, as well as much longer pulse length. Accordingly, the experimental program on ITER will embrace the study of issues of plasma physics and plasma-materials interactions that are specific to a reactor-scale fusion experiment. Such issues will include (i) confinement physics for a tokamak in which, for the first time, the core-plasma and the edge-plasma are simultaneously in a reactor-like regime; (ii) phenomena arising during plasma transients, including so-called disruptions, in regimes of high plasma current and thermal energy; and (iii) physics of a radiative divertor designed for handling high power flow for long pulses, including novel plasma and atomic-physics effects as well as materials science of surfaces subject to intense plasma interaction. Experiments on ITER will be conducted by researchers in control rooms situated at major fusion laboratories around the world, linked by high-speed computer networks--thus extending further what is already a much-acclaimed paradigm for international collaboration in science.

Rutherford, P.H.

1997-04-01T23:59:59.000Z

53

8.2. Indices and Iterators  

Science Conference Proceedings (OSTI)

... handled identically. Every Field , Flux , and Equation class has a function iterator() which returns an IteratorP object. The ...

2013-08-23T23:59:59.000Z

54

PPPL--2702 Power Radiated from ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

702 702 " Power Radiated from ITER and CIT by Impurities D E ~ O 014715 J. Cummings, S. A. Cohen, R Hulse, D. E. Post, M. H. Redi and J. Perkinst Princeton Plasma Physics Laboratory Princeton University, Rinceton, NJ 08543 Abstract The MIST code has been used to model impurity radiation from the edge and core plasmas in ITER and CIT. A broad range of parameters have been varied, including Zeff, impurity species, impurity transport coefficients, and plasma temperature and density profiles, especially at the edge. For a set of these parameters representative of the baseline ITER ignition scenario, it is seen that impurity radiation, which is produced in roughly equal amounts by the edge and core regions, can make a major improvement in divertor operation without compromising core

55

Iterational retiming: Maximize iteration-level parallelism for nested loops  

E-Print Network (OSTI)

Nested loops are the most critical sections in many scientific and Digital Signal Processing (DSP) applications. It is important to study effective and efficient transformation techniques to increase parallelism for nested loops. In this paper, we propose a novel technique, iterational retiming, that can satisfy any given timing constraint by achieving full parallelism for iterations in a partition. Theorems and efficient algorithms are proposed for iterational retiming. The experimental results show that iterational retiming is a promising technique for parallel embedded systems. It can achieve 87% improvement over software pipelining and 88 % improvement over loop unfolding on average.

Chun Xue; Zili Shao; Meilin Liu; Edwin H. -m. Sha

2005-01-01T23:59:59.000Z

56

Benchmarking ICRF simulations for ITER  

DOE Green Energy (OSTI)

Abstract Benchmarking of full-wave solvers for ICRF simulations is performed using plasma profiles and equilibria obtained from integrated self-consistent modeling predictions of four ITER plasmas. One is for a high performance baseline (5.3 T, 15 MA) DT H-mode plasma. The others are for half-field, half-current plasmas of interest for the pre-activation phase with bulk plasma ion species being either hydrogen or He4. The predicted profiles are used by seven groups to predict the ICRF electromagnetic fields and heating profiles. Approximate agreement is achieved for the predicted heating power partitions for the DT and He4 cases. Profiles of the heating powers and electromagnetic fields are compared.

R. V. Budny, L. Berry, R. Bilato, P. Bonoli, M. Brambilla, R.J. Dumont, A. Fukuyama, R. Harvey, E.F. Jaeger, E. Lerche, C.K. Phillips, V. Vdovin, J. Wright, and members of the ITPA-IOS

2010-09-28T23:59:59.000Z

57

Iterative solution of differential equations  

E-Print Network (OSTI)

We discuss alternative iteration methods for differential equations. We provide a convergence proof for exactly solvable examples and show more convenient formulas for nontrivial problems.

Paolo Amore; Hakan Ciftci; Francisco M. Fernandez

2006-09-29T23:59:59.000Z

58

Modelling iteration in engineering design  

E-Print Network (OSTI)

. United Kingdom. Phone +44 1223 332758 Fax +44 1223 332662 Email dcw24@cam.ac.uk URL http://www-edc.eng.cam.ac.uk/people/dcw24.html ICED’07/561 12 ...

Wynn, David C; Eckert, Claudia M; Clarkson, P John

59

EU signs ITER deal Negotiations on the ITER international nuclear  

E-Print Network (OSTI)

Korea and the US, the agreement aims to develop a project that will test the feasibility of nuclearEU signs ITER deal Negotiations on the ITER international nuclear fusion project have been parties will contribute up to ten per cent. European Greens, fiercely opposed to nuclear energy, have

60

An Iterative EnKF for Strongly Nonlinear Systems  

Science Conference Proceedings (OSTI)

The study considers an iterative formulation of the ensemble Kalman filter (EnKF) for strongly nonlinear systems in the perfect-model framework. In the first part, a scheme is introduced that is similar to the ensemble randomized maximal ...

Pavel Sakov; Dean S. Oliver; Laurent Bertino

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

An Iterative Radiative Transfer Code For Ocean-Atmosphere Systems  

Science Conference Proceedings (OSTI)

We describe the details of an iterative radiative transfer code for computing the intensity and degree of polarization of diffuse radiation in models of the ocean-atmosphere system. The present code neglects the upwelling radiation from below the ...

Ziauddin Ahmad; Robert S. Fraser

1982-03-01T23:59:59.000Z

62

ITER Engineering Design Activities ITER Technical Characteristics  

E-Print Network (OSTI)

on Construction Agreement and Site Selection (12/02) ¥ Construction begins in 2003. Divertor Remote Handling Project Vacuum Vessel Blanket Module Remote Handling Project Central Solenoid Model Coil Project Central

63

Princeton Plasma Physics Lab - ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

iter ITER is a large international iter ITER is a large international fusion experiment aimed at demonstrating the scientific and technological feasibility of fusion energy.ITER (Latin for "the way") will play a critical role advancing the worldwide availability of energy from fusion - the power source of the sun and the stars.To produce practical amounts of fusion power on earth, heavy forms of hydrogen are joined together at high temperature with an accompanying production of heat energy. The fuel must be held at a temperature of over 100 million degrees Celsius. At these high temperatures, the electrons are detached from the nuclei of the atoms, in a state of matter called plasma. en New imaging technique provides improved insight into controlling the plasma in fusion experiments

64

US ITER Project Providing a Facility for  

E-Print Network (OSTI)

US ITER Project Providing a Facility for Burning Plasma Research Ned Sauthoff Project Manager, US to position the US for Burning Plasma Research #12;U.S. ITER / Sauthoff Slide 2 Structure of the Talk... ITER

65

PTRANSP Tests Of TGLF And Predictions For ITER  

Science Conference Proceedings (OSTI)

One of the physics goals for ITER is to achieve high fusion power PDT at a high gain QDT. This goal is important for studying the physics of reactor-relevant burning plasmas. Simulations of plasma performance in ITER can help achieve this goal by aiding in the design of systems such as diagnostics and in planning ITER plasma regimes. Simulations can indicate areas where further research in theory and experiments is needed. To have credible simulations integrated modeling is necessary since plasma profiles and applied heating, torque, and current drive are strongly coupled.

Robert V. Budny, Xingqiu Yuan, S. Jardin, G. Hammett, G. Staebler, members of the ITPA Transport and Confinement Topical Group, and JET EFDA Contributions

2012-02-28T23:59:59.000Z

66

Rotating Plasma Finding is Key for ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

Plasma Finding is Key for ITER Rotating Plasma Finding is Key for ITER PlasmaTurbulenceCSChang.png Tokamak turbulence showing inward-propagating streamers from normalized...

67

Iterated dynamical maps in an ion trap  

E-Print Network (OSTI)

Iterated dynamical maps offer an ideal setting to investigate quantum dynamical bifurcations and are well adapted to few-qubit quantum computer realisations. We show that a single trapped ion, subject to periodic impulsive forces, exhibits a rich structure of dynamical bifurcations derived from the Jahn-Teller Hamiltonian flow model. We show that the entanglement between the oscillator and electronic degrees of freedom reflects the underlying dynamical bifurcation in a Floquet eigenstate.

M. Duncan; J. Links; G. J. Milburn

2007-11-16T23:59:59.000Z

68

Iterative Decoding and Turbo Equalization: The Z-Crease Phenomenon  

E-Print Network (OSTI)

Iterative probabilistic inference, popularly dubbed the soft-iterative paradigm, has found great use in a wide range of communication applications, including turbo decoding and turbo equalization. The classic approach of analyzing the iterative approach inevitably use the statistical and information-theoretical tools that bear ensemble-average flavors. This paper consider the per-block error rate performance, and analyzes it using nonlinear dynamical theory. By modeling the iterative processor as a nonlinear dynamical system, we report a universal "Z-crease phenomenon:" the zig-zag or up-and-down fluctuation -- rather than the monotonic decrease -- of the per-block errors, as the number of iteration increases. Using the turbo decoder as an example, we also report several interesting motion phenomenons which were not previously reported, and which appear to correspond well with the notion of "pseudo codewords" and "stopping/trapping sets." We further propose a heuristic stopping criterion to control Z-crease and identify the best iteration. Our stopping criterion is most useful for controlling the worst-case per-block errors, and helps to significantly reduce the average-iteration numbers.

Jing Li; Kai Xie

2013-06-03T23:59:59.000Z

69

ITER: Image Collections from the International Thermonuclear Experimental Reactor (ITER)  

DOE Data Explorer (OSTI)

ITER is a large-scale scientific experiment that aims to demonstrate that it is possible to produce commercial energy from fusion. The Q in the formula symbolizes the ratio of fusion power to input power. Q = 10 represents the scientific goal of the ITER project: to deliver ten times the power it consumes. From 50 MW of input power, the ITER machine is designed to produce 500 MW of fusion power - the first of all fusion experiments to produce net energy. During its operational lifetime, ITER will test key technologies necessary for the next step: the demonstration fusion power plant that will prove that it is possible to capture fusion energy for commercial use. The science going on at ITER - and all around the world in support of ITER - will benefit all of mankind. "We firmly believe that to harness fusion energy is the only way to reconcile huge conflicting demands which will confront humanity sooner or later. The issue at stake is how to reconcile the imperative, constantly growing demand of the majority of the world's population to raise their standard of living with the enormous environmental hazards resulting from the present energy supply. In our opinion, the use of fusion energy is a "must" if we want to be serious about embarking on sustainable development for future generations." Director-General Osamu Motojima, Opening address, Monaco International ITER Fusion Energy Days (MIIFED), 23 November 2010 [copied from http://www.iter.org/proj/itermission]. More than 900 images, organized into categories, are available as of 2013.

70

ITER Diagnostic First Wal  

Science Conference Proceedings (OSTI)

The ITER Diagnostic Division is responsible for designing and procuring the First Wall Blankets that are mounted on the vacuum vessel port plugs at both the upper and equatorial levels This paper will discuss the effects of the diagnostic aperture shape and configuration on the coolant circuit design. The DFW design is driven in large part by the need to conform the coolant arrangement to a wide variety of diagnostic apertures combined with the more severe heating conditions at the surface facing the plasma, the first wall. At the first wall, a radiant heat flux of 35W/cm2 combines with approximate peak volumetric heating rates of 8W/cm3 (equatorial ports) and 5W/cm3 (upper ports). Here at the FW, a fast thermal response is desirable and leads to a thin element between the heat flux and coolant. This requirement is opposed by the wish for a thicker FW element to accommodate surface erosion and other off-normal plasma events.

G. Douglas Loesser, et. al.

2012-09-21T23:59:59.000Z

71

A Reliable Technology to Manufacture the ITER Inner Vertical Target  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

Eliseo Visca; A. Pizzuto; B. Riccardi; S. Roccella; G. P. Sanguinetti

72

ITER Construction--Plant System Integration  

SciTech Connect

This brief paper introduces how the ITER will be built in the international collaboration. The ITER Organization plays a central role in constructing ITER and leading it into operation. Since most of the ITER components are to be provided in-kind from the member countries, integral project management should be scoped in advance of real work. Those include design, procurement, system assembly, testing, licensing and commissioning of ITER.

Tada, E. [ITER Organization Cadarache Center, 13108 St Paul lez Durance (France); Matsuda, S. [Japan Atomic Energy Research Agency, 100-0011, Chiyoda-ku, Tokyo (Japan)

2009-02-19T23:59:59.000Z

73

The Pugh Controlled Convergence Method: Model-Based Evaluation and Implications for Design Theory  

E-Print Network (OSTI)

This paper evaluates the Pugh Controlled Convergence method and its relationship to recent developments in design theory. Computer executable models are proposed simulating a team of people involved in iterated cycles of ...

Wijnia, Ype

74

Chaotic iterations and topological chaos  

E-Print Network (OSTI)

Chaotic iterations have been introduced on the one hand by Chazan, Miranker [5] and Miellou [9] in a numerical analysis context, and on the other hand by Robert [11] and Pellegrin [10] in the discrete dynamical systems framework. In both cases, the objective was to derive conditions of convergence of such iterations to a fixed state. In this paper, a new point of view is presented, the goal here is to derive conditions under which chaotic iterations admit a chaotic behaviour in a rigorous mathematical sense. Contrary to what has been studied in the literature, convergence is not desired. More precisely, we establish in this paper a link between the concept of chaotic iterations on a finite set and the notion of topological chaos [8], [6], [7]. We are motivated by concrete applications of our approach, such as the use of chaotic boolean iterations in the computer security field. Indeed, the concept of chaos is used in many areas of data security without real rigorous theoretical foundations, and without using the fundamental properties that allow chaos. The wish of this paper is to bring a bit more mathematical rigour in this field.

Jacques M. Bahi; Christophe Guyeux

2008-10-17T23:59:59.000Z

75

Iterative Collision Resolution in Wireless Networks  

E-Print Network (OSTI)

With the growing popularity of smart phones and tablets, development of multimedia applications is on the rise. Speedy transmission of this massive amount information is already pushing the limits of the capacity of wireless networks, and in upcoming years wireless data traffic is projected to continue increasing dramatically. Advances in wireless network throughput are necessary to keep up with society’s data demands. In an uncoordinated wireless communications system, transmissions collide and interfere as multiple users transmit data to a central receiver. Slotted-ALOHA, the conventional method that schedules user transmissions, has only 37% throughput efficiency. However, theoretical results in recent studies suggest that scheduling transmissions over a number of random, fixed timeslots and employing iterative collision resolution techniques achieves optimal throughput efficiency of approximately 100%. This research considers how real-world conditions affect these theoretical results. A MATLAB model was developed create random graphs, representing users transmitting packets over such timeslots, and the packets were resolved by this method. This model was simulated extensively, representing networks of up to 10,000 users over 10,000 to 15,000 timeslots, and the number of packets resolved in each iteration was measured. These simulations have generated empirical data that backs up the theoretical claim. The distribution of the number of packets resolved also led to modifications of the current model to increase the percentage of packets resolved in each iteration. Furthermore, by investigating low density parity check coding techniques, other modifications to the current model can optimize the throughput over several consecutive transmissions where unresolved packets are resent with higher probability of recovery. These results demonstrate the potential of this method in handling uncoordinated transmissions in communications systems, even in the presence of finite conditions. This suggests that this method could eventually be employed in actual wireless systems.

Stuckman, Katherine Christine

2013-05-01T23:59:59.000Z

76

Construction Safety Forecast for ITER  

SciTech Connect

The International Thermonuclear Experimental Reactor (ITER) project is poised to begin its construction activity. This paper gives an estimate of construction safety as if the experiment was being built in the United States. This estimate of construction injuries and potential fatalities serves as a useful forecast of what can be expected for construction of such a major facility in any country. These data should be considered by the ITER International Team as it plans for safety during the construction phase. Based on average U.S. construction rates, ITER may expect a lost workday case rate of < 4.0 and a fatality count of 0.5 to 0.9 persons per year.

cadwallader, lee charles

2006-11-01T23:59:59.000Z

77

The real mission of ITER  

DOE Green Energy (OSTI)

For future machines, the plasma stored energy is going up by factors of 20-40x, and plasma currents by 2-3x, while the surface to volume ratio is at the same time decreasing. Therefore the disruption forces, even for constant B, (which scale like IxB), and associated possible localized heating on machine components, are more severe. Notably, Tore Supra has demonstrated removal of more than 1 GJ of input energy, over nearly a 400 second period. However, the instantaneous stored energy in the Tore Supra system (which is most directly related to the potential for disruption damage) is quite small compared to other large tokamaks. The goal of ITER is routinely described as studying DT burning plasmas with a Q {approx} 10. In reality, ITER has a much more important first order mission. In fact, if it fails at this mission, the consequences are that ITER will never get to the eventual stated purpose of studying a burning plasma. The real mission of ITER is to study (and demonstrate successfully) plasma control with {approx}10-17 MA toroidal currents and {approx}100-400 MJ plasma stored energy levels in long-pulse scenarios. Before DT operation is ever given a go-ahead in ITER, the reality is that ITER must demonstrate routine and reliable control of high energy hydrogen (and deuterium) plasmas. The difficulty is that ITER must simultaneously deal with several technical problems: (1) heat removal at the plasma/wall interface, (2) protection of the wall components from off-normal events, and (3) generation of dust/redeposition of first wall materials. All previous tokamaks have encountered hundred's of major disruptions in the course of their operation. The consequences of a few MA of runaway electrons (at 20-50 MeV) being generated in ITER, and then being lost to the walls are simply catastrophic. They will not be deposited globally, but will drift out (up, down, whatever, depending on control system), and impact internal structures, unless 'ameliorated'. Basically, this represents an extraordinarily robust e-beam welding machine, capable of deep penetration into any armor tiles, to the cooling channels which are embedded less than 1 cm below the tile surface. When energy is deposited in a fraction of a second on (or in) a tile, the presence of underlying water cooling does no good for the purposes of heat removal.

Wurden, G A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

78

An Iterative Rejection Sampling Method.  

E-Print Network (OSTI)

ar X iv :0 80 7. 28 23 v1 [ he p- ph ] 17 Ju l 2 00 8 Preprint typeset in JHEP style - HYPER VERSION Cavendish-HEP-08/10 An Iterative Rejection Sampling Method A. Sherstnev Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue... , Cambridge, CB3 0HE, UK and Scobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University, Moscow, Russia, 119992 (on leave) Abstract: In the note we consider an iterative generalisation of the rejection sampling method. In high energy physics...

Sherstnev, A

79

Evaluation of ITER MSE Viewing Optics  

Science Conference Proceedings (OSTI)

The Motional Stark Effect (MSE) diagnostic on ITER determines the local plasma current density by measuring the polarization angle of light resulting from the interaction of a high energy neutral heating beam and the tokamak plasma. This light signal has to be transmitted from the edge and core of the plasma to a polarization analyzer located in the port plug. The optical system should either preserve the polarization information, or it should be possible to reliably calibrate any changes induced by the optics. This LLNL Work for Others project for the US ITER Project Office (USIPO) is focused on the design of the viewing optics for both the edge and core MSE systems. Several design constraints were considered, including: image quality, lack of polarization aberrations, ease of construction and cost of mirrors, neutron shielding, and geometric layout in the equatorial port plugs. The edge MSE optics are located in ITER equatorial port 3 and view Heating Beam 5, and the core system is located in equatorial port 1 viewing heating beam 4. The current work is an extension of previous preliminary design work completed by the ITER central team (ITER resources were not available to complete a detailed optimization of this system, and then the MSE was assigned to the US). The optimization of the optical systems at this level was done with the ZEMAX optical ray tracing code. The final LLNL designs decreased the ''blur'' in the optical system by nearly an order of magnitude, and the polarization blur was reduced by a factor of 3. The mirror sizes were reduced with an estimated cost savings of a factor of 3. The throughput of the system was greater than or equal to the previous ITER design. It was found that optical ray tracing was necessary to accurately measure the throughput. Metal mirrors, while they can introduce polarization aberrations, were used close to the plasma because of the anticipated high heat, particle, and neutron loads. These mirrors formed an intermediate image that then was relayed out of the port plug with more ideal (dielectric) mirrors. Engineering models of the optics, port plug, and neutral beam geometry were also created, using the CATIA ITER models. Two video conference calls with the USIPO provided valuable design guidelines, such as the minimum distance of the first optic from the plasma. A second focus of the project was the calibration of the system. Several different techniques are proposed, both before and during plasma operation. Fixed and rotatable polarizers would be used to characterize the system in the no-plasma case. Obtaining the full modulation spectrum from the polarization analyzer allows measurement of polarization effects and also MHD plasma phenomena. Light from neutral beam interaction with deuterium gas (no plasma) has been found useful to determine the wavelength of each spatial channel. The status of the optical design for the edge (upper) and core (lower) systems is included in the following figure. Several issues should be addressed by a follow-on study, including whether the optical labyrinth has sufficient neutron shielding and a detailed polarization characterization of actual mirrors.

Allen, S; Lerner, S; Morris, K; Jayakumar, J; Holcomb, C; Makowski, M; Latkowski, J; Chipman, R

2007-03-26T23:59:59.000Z

80

ITER CS Intermodule Support Structure  

Science Conference Proceedings (OSTI)

With five independently driven, bi-polarity power supplies, the modules of the ITER central solenoid (CS) can be energized in aligned or opposing field directions. This sets up the possibility for repelling modules, which indeed occurs, particularly between CS2L and CS3L around the End of Burn (EOB) time point. Light interface compression between these two modules at EOB and wide variations in these coil currents throughout the pulse produce a tendency for relative motion or slip. Ideally, the slip is purely radial as the modules breathe without any accumulative translational motion. In reality, however, asymmetries such as nonuniformity in intermodule friction, lateral loads from a plasma Vertical Disruption Event (VDE), magnetic forces from manufacturing and assembly tolerances, and earthquakes can all contribute to a combination of radial and lateral module motion. This paper presents 2D and 3D, nonlinear, ANSYS models which simulate these various asymmetries and determine the lateral forces which must be carried by the intermodule structure. Summing all of these asymmetric force contributions leads to a design-basis lateral load which is used in the design of various support concepts: the CS-CDR centering rings and a variation, the 2001 FDR baseline radial keys, and interlocking castles structures. Radial key-type intermodule structure interface slip and stresses are tracked through multiple 15 MA scenario current pulses to demonstrate stable motion following the first few cycles. Detractions and benefits of each candidate intermodule structure are discussed, leading to the simplest and most robust configuration which meets the design requirements: match-drilled radial holes and pin-shaped keys.

Myatt, R. [Myatt Consulting, Norfolk, MA; Freudenberg, Kevin D [ORNL

2011-01-01T23:59:59.000Z

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81

Neutronics at Wisconsin, ORNL advances ITER shielding and internationa...  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutronics at Wisconsin, ORNL advances ITER shielding and international collaboration American Fusion News Category: U.S. ITER Link: Neutronics at Wisconsin, ORNL advances ITER...

82

ITER movie created by Oak Ridge National Laboratory, National...  

NLE Websites -- All DOE Office Websites (Extended Search)

ITER movie created by Oak Ridge National Laboratory, National Center for Computational Sciences American Fusion News Category: U.S. ITER Link: ITER movie created by Oak Ridge...

83

BBC Video Looks at ITER | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Events Research Education Organization Contact Us BBC Video Looks at ITER American Fusion News Category: U.S. ITER Link: BBC Video Looks at ITER...

84

Evaluating iterative optimization across 1000 datasets  

Science Conference Proceedings (OSTI)

While iterative optimization has become a popular compiler optimization approach, it is based on a premise which has never been truly evaluated: that it is possible to learn the best compiler optimizations across data sets. Up to now, most iterative ... Keywords: benchmarking, compiler optimization, iterative optimization

Yang Chen; Yuanjie Huang; Lieven Eeckhout; Grigori Fursin; Liang Peng; Olivier Temam; Chengyong Wu

2010-06-01T23:59:59.000Z

85

An Iterative Scheme for Valid Polynomial Inequality Generation in ...  

E-Print Network (OSTI)

Computational results for quadratic knapsack instances. Values in bold are optimal. Lasserre. DIGS n Optimal r obj. t(sec) Iter. 0 Iter. 1 Iter. 5 Iter. 10 t(sec). 5 370.

86

Electromagnetic analysis of forces and torques on the ITER shield modules due to plasma disruption.  

SciTech Connect

An electromagnetic analysis is performed on the ITER shield modules under different plasma disruption scenarios using the OPERA-3d software. The modeling procedure is explained, electromagnetic torques are presented, and results of the modeling are discussed.

Kotulski, Joseph Daniel; Coats, Rebecca Sue; Pasik, Michael Francis; Ulrickson, Michael Andrew

2009-06-01T23:59:59.000Z

87

An Iterative Rejection Sampling Method  

E-Print Network (OSTI)

In the note we consider an iterative generalisation of the rejection sampling method. In high energy physics, this sampling is frequently used for event generation, i.e. preparation of phase space points distributed according to a matrix element squared $|M|^2$ for a scattering process. In many realistic cases $|M|^2$ is a complicated multi-dimensional function, so, the standard von Neumann procedure has quite low efficiency, even if an error reducing technique, like VEGAS, is applied. As a result of that, many of the $|M|^2$ calculations go to ``waste''. The considered iterative modification of the procedure can extract more ``unweighted'' events, i.e. distributed according to $|M|^2$. In several simple examples we show practical benefits of the technique and obtain more events than the standard von Neumann method, without any extra calculations of $|M|^2$.

A. Sherstnev

2008-07-17T23:59:59.000Z

88

usion Technology for ITER, the ITER Project. Further Development Towards a DEMO Fusion Power Plant (4/4)  

E-Print Network (OSTI)

usion Technology for ITER, the ITER Project. Further Development Towards a DEMO Fusion Power Plant (4/4)

CERN. Geneva

2011-01-01T23:59:59.000Z

89

Power radiated from ITER and CIT by impurities  

Science Conference Proceedings (OSTI)

The MIST code has been used to model impurity radiation from the edge and core plasmas in ITER and CIT. A broad range of parameters have been varied, including Z{sub eff}, impurity species, impurity transport coefficients, and plasma temperature and density profiles, especially at the edge. For a set of these parameters representative of the baseline ITER ignition scenario, it is seen that impurity radiation, which is produced in roughly equal amounts by the edge and core regions, can make a major improvement in divertor operation without compromising core energy confinement. Scalings of impurity radiation with atomic number and machine size are also discussed. 22 refs., 16 figs.

Cummings, J.; Cohen, S.A.; Hulse, R.; Post, D.E.; Redi, M.H.; Perkins, J.

1990-07-01T23:59:59.000Z

90

Development of A-LITE Model for Use in ATTILA Radiation Transport Finite Element Analysis of the ITER Lower Divertor Region  

Science Conference Proceedings (OSTI)

Computational Tools, Modeling & Validation / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 2)

Aaron T. Aoyama; Mohamad Dagher; Russell Feder; Michael Duco; Mahmoud Youssef

91

ITER Central Solenoid support structure analysis  

Science Conference Proceedings (OSTI)

The ITER Central Solenoid (CS) is comprised of six independent coils held together by a pre-compression support structure. This structure must provide enough preload to maintain sufficient coil-to-coil contact and interface load throughout the current pulse. End of burn (EOB) represents one of the most extreme time-points doing the reference scenario when the currents in the CS3 coils oppose those of CS1 & CS2. The CS structure is performance limited by the room temperature static yield requirements needed to support the roughly 180 MN preload to resist coil separation during operation. This preload is applied by inner and external tie plates along the length of the coil stack by mechanical fastening methods utilizing Superbolt technology. The preloading structure satisfies the magnet structural design criteria of ITER and will be verified during mockup studies. The solenoid is supported from the bottom of the toroidal field (TF) coil casing in both the vertical radial directions. The upper support of the CS coil structure maintains radial registration with the TF coil in the event of vertical disruptions (VDE) loads and earthquakes. All of these structure systems are analyzed via a global finite element analysis (FEA). The model includes a complete sector of the TF coil and the CS coil/structure in one self-consistent analysis. The corresponding results and design descriptions are described in this report.

Freudenberg, Kevin D [ORNL; Myatt, R. [Myatt Consulting, Norfolk, MA

2011-01-01T23:59:59.000Z

92

Simulations of plasma behavior during pellet injection in ITER  

SciTech Connect

Plasma behavior during pellet injection in ITER is investigated using a 1.5D BALDUR integrated predictive modeling code. In these simulations, the pellet ablation is described using the neutral gas shielding (NGS) model developed by Parks and Turnbull [Phys. Fluids 21, 1735 (1978)]. The NGS pellet ablation model that includes the {nabla}B drift effect is coupled with a plasma core transport model, which is a combination of an MMM95 anomalous transport model and an NCLASS neoclassical transport model. The combination of core transport models, together with pellet model, is used to simulate the time evolution of plasma current, ion and electron temperatures, and density profiles for ITER standard type-I ELMy H-mode discharges during the pellet injection. It is found that the injection of pellet can result in either enhancement or degradation of plasma performance. The {nabla}B drift effect on the pellet deposition is very strong in ITER. The plasma density with high field side pellets, which favorable with the {nabla}B drift effect, is much higher and pellet can penetrate much deeper than that with low field side pellets.

Klaywittaphat, P., E-mail: thawatchai@siit.tu.ac.th; Onjun, T. [Thammasat University, School of Manufacturing Systems and Mechanical Engineering, Sirindhorn International Institute of Technology (Thailand)

2012-06-15T23:59:59.000Z

93

ITER Test Program: Key Technical Aspects  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Ninth Topical Meeting on the Technology of Fusion Energy (Oak Brook, Illinois, October 7-11, 1990)

Mohamed A. Abdou

94

Availability Requirement for ITER Plasma Parameter Measurements  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

K. Okayama; D. van Houtte; F. Sagot; M. Walsh

95

Improving robustness of ITER maintenance schedules.  

E-Print Network (OSTI)

?? In the experimental ITER fusion reactor, currently under construction in Cadarache, France, components close to the plasma will get activated and contaminated over time.… (more)

Schoen, Pepijn

2013-01-01T23:59:59.000Z

96

An overview of ITER diagnostics (invited)  

Science Conference Proceedings (OSTI)

The requirements for plasma measurements for operating and controlling the ITER device have now been determined. Initial criteria for the measurement quality have been set

Kenneth M. Young; A. E. Costley; Members of the ITER-JCT, ITER Home Teams and the ITER Diagnostics Expert Group

1997-01-01T23:59:59.000Z

97

Overview of ITER ProjectOverview of ITER Project --organizational structure,organizational structure,  

E-Print Network (OSTI)

/Research Plans 3. Basic Research in support of ITER · Experimental and Theoretical Plasma Research · R

98

On the Green's function and iterative solutions of Loop Quantum Cosmology  

E-Print Network (OSTI)

Here we shall find the green's function of the difference equation of loop quantum cosmology. To illustrate how to use it, we shall obtain an iterative solution for closed model and evaluate its corresponding Bohmian trajectory.

Fatimah Shojai; Ali Shojai

2006-07-09T23:59:59.000Z

99

Nonlinear forecasting and iterated function systems  

Science Conference Proceedings (OSTI)

The theory of dynamical forecasting can be extended to iterated function systems. An unordered set of iterates may be sufficient to construct a simulation of the unknown dynamics. The underlying dynamical system may be nondeterministic: A random element may be allowed in the dynamics

Giorgio Mantica; B. G. Giraud

1992-01-01T23:59:59.000Z

100

Iterative equalization and decoding applied to underwater acoustic communication  

E-Print Network (OSTI)

absolute phase error versus iter- ation. (d) Number of bitCMP estimation are done iter- atively, in conjunction withAPP estimates ? (i) . If i = N iter , then the sym- bol APP

Sifferlen, James F.

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

A Model of the Internal Feedback System Involved in Late Quaternary Climatic Variations  

Science Conference Proceedings (OSTI)

Because of the small net rates of energy flow involved in very long-term changes in ice mass (10?1 W m?2) it will be impossible to proceed in a purely deductive manner to develop a theory for these changes. An inductive approach will be necessary-...

Barry Saltzman; Alfonso Sutera

1984-03-01T23:59:59.000Z

102

A comparative study of iterative solutions to linear systems arising in quantum mechanics  

Science Conference Proceedings (OSTI)

This study is mainly focused on iterative solutions with simple diagonal preconditioning to two complex-valued nonsymmetric systems of linear equations arising from a computational chemistry model problem proposed by Sherry Li of NERSC. Numerical experiments show the feasibility of iterative methods to some extent when applied to the problems and reveal the competitiveness of our recently proposed Lanczos biconjugate A-orthonormalization methods to other classic and popular iterative methods. By the way, experiment results also indicate that application specific preconditioners may be mandatory and required for accelerating convergence.

Jing Yanfei, E-mail: yanfeijing@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Huang Tingzhu, E-mail: tzhuang@uestc.edu.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Duan Yong, E-mail: duanyong@yahoo.c [School of Mathematical Sciences/Institute of Computational Science, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731 (China); Carpentieri, Bruno, E-mail: b.carpentieri@rug.n [Institute of Mathematics and Computing Science, University of Groningen, Nijenborgh 9, P.O. Box 407, 9700 AK Groningen (Netherlands)

2010-11-01T23:59:59.000Z

103

iterative regularization in intensity-modulated radiation therapy ...  

E-Print Network (OSTI)

For iter* to be a meaningful parameter, the optimization solver should initially proceed ... When the optimization problem is ill-conditioned, iter* will be very small ...

104

International Workshop: MFE Roadmapping in the ITER Era | Princeton...  

NLE Websites -- All DOE Office Websites (Extended Search)

International Workshop: MFE Roadmapping in the ITER Era International Workshop: MFE Roadmapping in the ITER Era Contact Information Website: International Workshop: MFE Roadmapping...

105

Iterators can be independent “from” their collections  

E-Print Network (OSTI)

External iterators pose problems for alias control mechanisms: they have access to collection interals and yet are not accessible from the collection; they may be used in contexts that are unaware of the collection. And yet iterators can benefit from alias control because iterators may fail “unexpectedly ” when their collections are modified. We explain a novel aliasing annotation “from ” that indicates when a collection intends to delegate its access to internals to a new object and how it can be given semantics using a fractional permission system. We sketch how a static analysis using permissions can statically detect possible concurrent modification exceptions. 1.

John Boyland

2007-01-01T23:59:59.000Z

106

Fabrication Preparation of ITER Vacuum Vessel - Material Considerations, Regulatory Requirements, and Fabrication Plans  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

K. Ioki; C. H. Choi; E. Daly; S. Dani; J. Davis; B. Giraud; C. Hamlyn-Harris; G. Johnson; L. Jones; C. Jun; B. C. Kim; E. Kuzmin; R. Le Barbier; J-M. Martinez; H. Pathak; J. Preble; J. Reich; J. W. Sa; A. Terasawa; Yu. Utin; X. Wang; S. Wu

107

The Development of Material and Fabrication Technologies for ITER Magnet Supports  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

P. Y. Li; C. J. Pan; B. L. Hou; S. L. Han; Z. C. Sun; F. Savary; Y. K. Fu; R. Gallix; N. Mitchell

108

Investigations of Radiation Damage Effects on ITER Structural and Plasma-Facing Materials  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

A. I. Ryazanov; V. S. Koidan; B. I. Khripunov; S. T. Latushkin; V. B. Petrov; L. S. Danelyan; E. V. Semenov; V. N. Unezhev

109

Analyses and Preliminary Results of an Updated ITER Radioactive Waste Assessment  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

S. Zheng; R. Pampin; S. Lilley; B. C. Na; M. J. Loughlin; N. P. Taylor; V. Barabash

110

A model of hyphal tip growth involving microtubule-based transport  

E-Print Network (OSTI)

We propose a simple model for mass transport within a fungal hypha and its subsequent growth. Inspired by the role of microtubule-transported vesicles, we embody the internal dynamics of mass inside a hypha with mutually excluding particles progressing stochastically along a growing one-dimensional lattice. The connection between long range transport of materials for growth, and the resulting extension of the hyphal tip has not previously been addressed in the modelling literature. We derive and analyse mean-field equations for the model and present a phase diagram of its steady state behaviour, which we compare to simulations. We discuss our results in the context of the filamentous fungus, Neurospora crassa.

K. E. P. Sugden; M. R. Evans; W. C. K. Poon; N. D. Read

2006-05-09T23:59:59.000Z

111

The community environmental monitoring program: a model for stakeholder involvement in environmental monitoring  

Science Conference Proceedings (OSTI)

Since 1981, the Community Environmental Monitoring Program (CEMP) has involved stakeholders directly in its daily operation and data collection, as well as in dissemination of information on radiological surveillance in communities surrounding the Nevada Test Site (NTS), the primary location where the United States (US) conducted nuclear testing until 1992. The CEMP is funded by the US Department of Energy's National Nuclear Security Administration, and is administered by the Desert Research Institute (DRI) of the Nevada System of Higher Education. The CEMP provides training workshops for stakeholders involved in the program, and educational outreach to address public concerns about health risk and environmental impacts from past and ongoing NTS activities. The network includes 29 monitoring stations located across an approximately 160,000 km{sup 2} area of Nevada, Utah and California in the southwestern US. The principal radiological instruments are pressurized ion chambers for measuring gamma radiation, and particulate air samplers, primarily for alpha/beta detection. Stations also employ a full suite of meteorological instruments, allowing for improved interpretation of the effects of meteorological events on background radiation levels. Station sensors are wired to state-of-the-art data-loggers that are capable of several weeks of on-site data storage, and that work in tandem with a communications system that integrates DSL and wireless internet, land line and cellular phone, and satellite technologies for data transfer. Data are managed through a platform maintained by the Western Regional Climate Center (WRCC) that DRI operates for the U.S. National Oceanic and Atmospheric Administration. The WRCC platform allows for near real-time upload and display of current monitoring information in tabular and graphical formats on a public web site. Archival data for each station are also available on-line, providing the ability to perform trending analyses or calculate site-specific exposure rates. This configuration also allows for remote programming and troubleshooting of sensors. Involvement of stakeholders in the monitoring process provides a number of benefits, including increased public confidence in monitoring results, as well as decreasing costs by more than 50 percent from when the program was managed entirely by U.S. federal employees. Additionally, the CEMP provides an ideal platform for testing new environmental sensors. (authors)

Hartwell, William T. [Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, Nevada (United States); Shafer, David S. [Division of Hydrological Sciences, Desert Research Institute, Las Vegas, Nevada (United States)

2007-07-01T23:59:59.000Z

112

Iterated Differential Forms II: Riemannian Geometry Revisited  

E-Print Network (OSTI)

A natural extension of Riemannian geometry to a much wider context is presented on the basis of the iterated differential form formalism developed in math.DG/0605113 and an application to general relativity is given.

A. M. Vinogradov; L. Vitagliano

2006-09-11T23:59:59.000Z

113

Iterated maps for clarinet-like systems  

E-Print Network (OSTI)

The dynamical equations of clarinet-like systems are known to be reducible to a non-linear iterated map within reasonable approximations. This leads to time oscillations that are represented by square signals, analogous to the Raman regime for string instruments. In this article, we study in more detail the properties of the corresponding non-linear iterations, with emphasis on the geometrical constructions that can be used to classify the various solutions (for instance with or without reed beating) as well as on the periodicity windows that occur within the chaotic region. In particular, we find a regime where period tripling occurs and examine the conditions for intermittency. We also show that, while the direct observation of the iteration function does not reveal much on the oscillation regime of the instrument, the graph of the high order iterates directly gives visible information on the oscillation regime (characterization of the number of period doubligs, chaotic behaviour, etc.).

Pierre-André Taillard; Jean Kergomard; Franck Laloë

2009-12-12T23:59:59.000Z

114

Iterative and Incremental Development: A Brief History  

Science Conference Proceedings (OSTI)

Although many view iterative and incremental development as a modern practice, its application dates as far back as the mid-1950s. Prominent software-engineering thought leaders from each succeeding decade supported IID practices, and many large projects ...

Craig Larman; Victor R. Basili

2003-06-01T23:59:59.000Z

115

Michel Claessens michel.claessens@iter.org  

E-Print Network (OSTI)

on the manufacturing of critical components, were among the important issues discussed at the eighth meeting. Photos of the Council Meeting can be found at: http://www.iter.org/gallery/pr_2011_06_ic8 Additional

116

French landmark decree authorizes ITER construction | Princeton...  

NLE Websites -- All DOE Office Websites (Extended Search)

ITER construction By John Greenwald November 20, 2012 Tweet Widget Facebook Like Google Plus One The French government has capped more than two years of review by issuing a...

117

Iterative entanglement distillation for finite resources  

E-Print Network (OSTI)

We discuss a specific entanglement distillation scheme under the constraint of finite samples of entangled qubit pairs. It is shown that an iterative process can be explicitly formulated. The average fidelity of this process can be enhanced by introducing conditional storing of entangled qubit pairs in each step of the iteration. We investigate the corresponding limitations on the size and the initial fidelity of the sample.

Stefan Probst-Schendzielorz; Thorsten Bschorr; Matthias Freyberger

2005-06-20T23:59:59.000Z

118

Adaptive iterative multiscale finite volume method  

Science Conference Proceedings (OSTI)

The multiscale finite volume (MSFV) method is a computationally efficient numerical method for the solution of elliptic and parabolic problems with heterogeneous coefficients. It has been shown for a wide range of test cases that the MSFV results are ... Keywords: Adaptive multiscale method, Elliptic problem, Infrequently localization improvement, Iterative multiscale finite-volume method, Iterative multiscale method, Multiphase flow, Multiscale finite-volume method, Multiscale method, Porous media

Hadi Hajibeygi; Patrick Jenny

2011-02-01T23:59:59.000Z

119

Gas species, their evolution and segregation through the ITER vacuum systems  

SciTech Connect

This paper takes the ITER fueling requirements and current knowledge of gas balance and exhaust from operating tokamaks to predict all likely gas inputs into the ITER Vacuum systems. Areas where gas dynamics modeling is relevant to the ITER design are highlighted. The design and operation of the ITER vacuum system gives an element of segregation of different gas flows and species. This paper analyses the time dependent gas segregation in the vacuum system resulting from different temperature dependences of cryogenic sorption and condensation processes of different gas species. As a specific example, the optimal transfer of Ar-41 through the vacuum system is studied with respect to its decay and the resulting effects on the design of system components.

Pearce, R.J.H. [ITER Organization, Cadarache, France; Antipenkov, Alexander [ITER Joint Work Site, Cadarache; Bersier, Jean-Louis [ITER Joint Work Site, Cadarache; Boussier, Bastien [ITER Joint Work Site, Cadarache; Baylor, Larry R [ORNL; Gardner, Walter L [ORNL; Meitner, Steven J [ORNL

2012-01-01T23:59:59.000Z

120

Using dual decomposition for solving problems involving data uncertainty |  

NLE Websites -- All DOE Office Websites (Extended Search)

dual decomposition for solving problems involving data uncertainty dual decomposition for solving problems involving data uncertainty August 14, 2013 Tweet EmailPrint Many applications mdash; energy, routing, scheduling, and production planning, for example mdash; involve problems in which some or all of the data may not be known when decisions under uncertainty must be made. In such cases, approximations with stochastic mixed-integer programming models are often used. Two approaches have been suggested to address such problems: dual decomposition (DD) and branch-and-price (BP). Both approaches divide the problem into two or more subproblems, together with linear constraints that enforce agreement between solutions to the different problems through a series of iterations. Unfortunately, both approaches also suffer from lack

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Co-relation of Variables Involved in the Occurrence of Crane Accidents in U.S. through Logit Modeling.  

E-Print Network (OSTI)

One of the primary reasons of the escalating rates of injuries and fatalities in the construction industry is the ever so complex, dynamic and continually changing nature of construction work. Use of cranes has become imperative to overcome technical challenges, which has lead to escalation of danger on a construction site. Data from OSHA show that crane accidents have increased rapidly from 2000 to 2004. By analyzing the characteristics of all the crane accident inspections, we can better understand the significance of the many variables involved in a crane accident. For this research, data were collected from the U.S. Department of Labor website via the OSHA database. The data encompass crane accident inspections for all the states. The data were divided into categories with respect to accident types, construction operations, degree of accident, fault, contributing factors, crane types, victim’s occupation, organs affected and load. Descriptive analysis was performed to compliment the previous studies, the only difference being that both fatal and non-fatal accidents have been considered. Multinomial regression has been applied to derive probability models and correlation between different accident types and the factors involved for each crane accident type. A log likelihood test as well as chi-square test was performed to validate the models. The results show that electrocution, crane tip over and crushed during assembly/disassembly have more probability of occurrence than other accident types. Load is not a significant factor for the crane accidents, and manual fault is more probable a cause for crane accident than is technical fault. Construction operations identified in the research were found to be significant for all the crane accident types. Mobile crawler crane, mobile truck crane and tower crane were found to be more susceptible. These probability models are limited as far as the inculcation of unforeseen variables in construction accidents are concerned. In fact, these models utilize the past to portray the future, and therefore significant change in the variables involved is required to be added to attain correct and expedient results.

Bains, Amrit Anoop Singh

2010-08-01T23:59:59.000Z

122

An Iterative Solver with a Convergence-Acceleration Technique for Pressure Field in an Uneven-Spacing Grid System  

Science Conference Proceedings (OSTI)

A straightforward iterative method is developed for solving the pressure field in three-dimensional, anelastic, nonhydrostatic, mesoscale models with uneven-spacing grid systems for which direct FFT (fan Fourier transform) schemes cannot be ...

Chih-Yue Jim Kao; Lawrence H. Auer

1990-07-01T23:59:59.000Z

123

Non-iterative and exact method for constraining particles in a linear geometry  

E-Print Network (OSTI)

We present a practical numerical method for evaluating the Lagrange multipliers necessary for maintaining a constrained linear geometry of particles in dynamical simulations. The method involves no iterations, and is limited in accuracy only by the numerical methods for solving small systems of linear equations. As a result of the non-iterative and exact (within numerical accuracy) nature of the procedure there is no drift in the constrained geometry, and the method is therefore readily applied to molecular dynamics simulations of, e.g., rigid linear molecules or materials of non-spherical grains. We illustrate the approach through implementation in the commonly used second-order velocity explicit Verlet method.

Horacio Tapia-McClung; Niels Grønbech-Jensen

2004-12-21T23:59:59.000Z

124

Feasibility Study of Lost-Alpha-Particle Measurements by Probe Technique in ITER  

Science Conference Proceedings (OSTI)

Technical Paper by Monaco ITER Postdoctoral Fellows / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

E. A. Veshchev; L. Bertalot; S. Putvinski; M. Garcia-Munoz; S. W. Lisgo; C. S. Pitcher; R. A. Pitts; V. S. Udintsev; M. Walsh

125

Plasma-Wall-Interaction Diagnostics in ITER: Dust, Erosion, and Tritium Retention  

Science Conference Proceedings (OSTI)

Technical Paper by Monaco ITER Postdoctoral Fellows / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

Junghee Kim; P. Andrew; R. Reichle

126

US ITER is a strong contributor in plan to enhance international...  

NLE Websites -- All DOE Office Websites (Extended Search)

American Fusion News Category: U.S. ITER Link: US ITER is a strong contributor in plan to enhance international sharing of prime ITER real estate...

127

Joint News Release ELEVENTH ITER NEGOTIATIONS MEETING  

E-Print Network (OSTI)

Joint News Release ELEVENTH ITER NEGOTIATIONS MEETING CHENGDU , CHINA, 24OCTOBER 2005 Delegations of America met in CHENGDU on 24October 2005 to continue their work to reach agreement on the joint the project and its procurements, and the continuing joint drafting of the agreement on establishing

128

The ITER budget is projected to be  

E-Print Network (OSTI)

, including 4.7 billion euros to build the reactor. BACK FRANCE AND JAPAN FAIL TO RESOLVE ROW ON NUCLEAR to resolve their differences on where to build a revolutionary nuclear fusion project, with Foreign Minister Experimental Reactor (ITER) in France without Japan if an agreement with Tokyo is not reached "as soon

129

ITERATIVE METHODS FOR NEUTRON TRANSPORT EIGENVALUE PROBLEMS  

E-Print Network (OSTI)

Abstract. We discuss iterative methods for computing criticality in nuclear reactors. In general the safety and optimal performance of existing nuclear reactors is an important task of great environmental significance. When operating a nuclear reactor, the engineer seeks to achieve a sustainable chain reaction

Graham, Ivan

130

Iterated local search in nurse rostering problem  

Science Conference Proceedings (OSTI)

This paper presents how to solve a nurse rostering problem over the real datasets of Centre hospitalier régional de Trois-Rivières hospital in Canada. Due to the complexity of this problem with plenty of hard constraints, we propose an ... Keywords: greedy, iterated local search, nurse rostering, tabu search

Sen Ngoc Vu, Minh H. Nhat Nguyen, Le Minh Duc, Chantal Baril, Viviane Gascon, Tien Ba Dinh

2013-12-01T23:59:59.000Z

131

Axisymmetric Simulations of the ITER Vertical Stability Coil  

SciTech Connect

The ITER in-vessel coil system includes Vertical Stability (VS) coils and Edge Localized Mode (ELM) coils. There are two large VS ring coils, one upper and one lower. Each has four turns which are independently connected. The VS coils are needed for successful operation of ITER for most all of its operating modes. The VS coils must be highly reliable and fault tolerant. The operating environment includes normal and disruption Lorentz forces. To parametrically address all these design conditions in a tractable analysis requires a simplified model. The VS coils are predominately axisymmetric, and this suggests that an axisymmetric model can be meaningfully used to address the variations in mechanical design, loading, material properties, and time dependency. The axisymmetric finite element analysis described in this paper includes simulations of the bolted frictional connections used for the mounting details. Radiation and elastic-plastic response are modeled particularly for the extreme faulted conditions. Thermal connectivity is varied to study the effects of partial thermal connection of the actively cooled conductor to the remaining structure.

Titus, Peter H.

2013-07-09T23:59:59.000Z

132

Optimizing ITER Power Supplies Operation Through RAMI and Standardization  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

François Sagot; Didier van Houtte; Katsumi Okayama; Joel Hourtoule; Inho Song

133

Budget Planning Meeting FY 2007 Status of ITER Negotiations  

E-Print Network (OSTI)

March 22-24 · CDs-2-4 are more dependent upon the reviews by the ITER Organization (to be formed-level discussion on ITER held in DOE HQ, Washington, DC · Requested a comprehensive briefing on ITER #12;FY2006 Agreement per H.R. 610 Form ITER Organization Begin funding for personnel FY2006 Pres Request of $49.5M

134

Optimization Online - "Block-Iterative and String-Averaging ...  

E-Print Network (OSTI)

Jul 19, 2009 ... Optimization Online. "Block-Iterative and String-Averaging Projection Algorithms in Proton Computed Tomography Image Reconstruction".

135

Princeton Plasma Physics Lab - U.S. ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

iter U.S. ITER en BBC iter U.S. ITER en BBC Video Looks at ITER http://www.pppl.gov/node/1536

American Fusion News Category: 
iter">U.S. ITER
136

Technological Institute of Renewable Energy ITER | Open Energy Information  

Open Energy Info (EERE)

Renewable Energy ITER Renewable Energy ITER Jump to: navigation, search Name Technological Institute of Renewable Energy (ITER) Place Santa Cruz de Tenerife, Spain Zip 38611 Sector Solar, Wind energy Product Spain-based, technological research and development institute focused on the solar and wind sectors. References Technological Institute of Renewable Energy (ITER)[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Technological Institute of Renewable Energy (ITER) is a company located in Santa Cruz de Tenerife, Spain . References ↑ "Technological Institute of Renewable Energy (ITER)" Retrieved from "http://en.openei.org/w/index.php?title=Technological_Institute_of_Renewable_Energy_ITER&oldid=352069

137

Shortcuts to adiabaticity by superadiabatic iterations  

E-Print Network (OSTI)

Different techniques to speed up quantum adiabatic processes are currently being explored for applications in atomic, molecular and optical physics, such as transport, cooling and expansions, wavepacket splitting, or internal state control. Here we examine the capabilities of superadiabatic iterations to produce a sequence of shortcuts to adiabaticity. The general formalism is worked out as well as examples for population inversion in a two-level system.

S. Ibáñez; Xi Chen; J. G. Muga

2012-12-27T23:59:59.000Z

138

Iterative solutions to the Dirac equation  

E-Print Network (OSTI)

We consider a single particle which is bound by a central potential and obeys the Dirac equation in d dimensions. We first apply the asymptotic iteration method to recover the known exact solutions for the pure Coulomb case. For a screened-Coulomb potential and for a Coulomb plus linear potential with linear scalar confinement, the method is used to obtain accurate approximate solutions for both eigenvalues and wave functions.

Hakan Ciftci; Richard L. Hall; Nasser Saad

2005-05-26T23:59:59.000Z

139

Iterative receivers for OFDM systems with dispersive fading and frequency offset  

E-Print Network (OSTI)

The presence of dispersive fading and inter-carrier interference (ICI) constitute the major impediment to reliable communications in orthogonal frequency-division multiplexing (OFDM) systems. Recently iterative (``Turbo'') processing techniques, which have been successfully applied to many detection/decoding problems, have received considerable attention. In this thesis, we first aim on the design of iterative receiver for single antenna OFDM system with frequency offset and dispersive fading. Further work is then extended to space-time block coded (STBC) OFDM system. At last, the technique is applied to STBC-OFDM system through a newly built channel model, which is based on a physical description of the propagation environment. The performance of such systems are verified by computer simulations. The simulation results show that the iterative techniques work well in OFDM systems.

Liu, Hui

2005-05-01T23:59:59.000Z

140

Bandwidth Allocation for Iterative Data-Dependent E-science Applications  

Science Conference Proceedings (OSTI)

We develop a novel framework for supporting e-Science applications that require streaming of information between sites. Using a Synchronous Dataflow (SDF) model, our framework incorporates the communication times inherent in large scale distributed applications, ... Keywords: Bandwidth allocation, Throughput, Iterative datadependent, E-Science

Eun-Sung Jung; Sanjay Ranka; Sartaj Sahni

2010-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Principal component analysis of binary data by iterated singular value decomposition  

Science Conference Proceedings (OSTI)

The maximum-likelihood estimates of a principal component analysis on the logit or probit scale are computed using majorization algorithms that iterate a sequence of weighted or unweighted singular value decompositions. The relation with similar methods ... Keywords: Applications to social sciences, Binary data, Factor analysis, Item response models, Multivariate analysis

Jan de Leeuw

2006-01-01T23:59:59.000Z

142

HEART SEGMENTATION WITH AN ITERATIVE CHAN-VESE OLIVIER ROUSSEAU, YVES BOURGAULT  

E-Print Network (OSTI)

HEART SEGMENTATION WITH AN ITERATIVE CHAN-VESE ALGORITHM OLIVIER ROUSSEAU, YVES BOURGAULT Abstract. This paper presents 2D and 3D applications of the Chan-Vese model to heart and trachea segmentation. We is to segment the heart muscle from high resolution CT scans of the thorax and to produce meshes

Paris-Sud XI, Université de

143

Iterative methods for solving the pressure problem at multiphase filtration  

E-Print Network (OSTI)

Applied problems of oil and gas recovery are studied numerically using the mathematical models of multiphase fluid flows in porous media. The basic model includes the continuity equations and the Darcy laws for each phase, as well as the algebraic expression for the sum of saturations. Primary computational algorithms are implemented for such problems using the pressure equation. In this paper, we highlight the basic properties of the pressure problem and discuss the necessity of their fulfillment at the discrete level. The resulting elliptic problem for the pressure equation is characterized by a non-selfadjoint operator. Possibilities of approximate solving the elliptic problem are considered using the iterative methods. Special attention is given to the numerical algorithms for calculating the pressure on parallel computers.

Vabishchevich, P

2011-01-01T23:59:59.000Z

144

Occupational Radiation Exposure Analysis of US ITER DCLL TBM  

Science Conference Proceedings (OSTI)

This report documents an Occupational Radiation Exposure (ORE) analysis that was performed for the US International Thermonuclear Experimental Reactor (ITER) Dual Coolant Lead Lithium (DCLL) Test Blanket Module (TBM). This analysis was performed with the QADMOD dose code for anticipated maintenance activities for this TBM concept and its ancillary systems. The QADMOD code was used to model the PbLi cooling loop of this TBM concept by specifying gamma ray source terms that simulated radioactive material within the piping, valves, heat exchanger, permeator, pump, drain tank, and cold trap of this cooling system. Estimates of the maintenance tasks that will have to be performed and the time required to perform these tasks where developed based on either expert opinion or on industrial maintenance experience for similar technologies. This report details the modeling activity and the calculated doses for the maintenance activities envisioned for the US DCLL TBM.

Merrill, Brad J; Cadwallader, Lee C; Dagher, Mohamad

2007-08-01T23:59:59.000Z

145

Physics and technology in the ion-cyclotron range of frequency on Tore Supra and TITAN test facility: implication for ITER  

SciTech Connect

To support the design of an ITER ion-cyclotron range of frequency heating (ICRH) system and to mitigate risks of operation in ITER, CEA has initiated an ambitious Research & Development program accompanied by experiments on Tore Supra or test-bed facility together with a significant modelling effort. The paper summarizes the recent results in the following areas: Comprehensive characterization (experiments and modelling) of a new Faraday screen concept tested on the Tore Supra antenna. A new model is developed for calculating the ICRH sheath rectification at the antenna vicinity. The model is applied to calculate the local heat flux on Tore Supra and ITER ICRH antennas. Full-wave modelling of ITER ICRH heating and current drive scenarios with the EVE code. With 20 MW of power, a current of 400 kA could be driven on axis in the DT scenario. Comparison between DT and DT(3He) scenario is given for heating and current drive efficiencies. First operation of CW test-bed facility, TITAN, designed for ITER ICRH components testing and could host up to a quarter of an ITER antenna. R&D of high permittivity materials to improve load of test facilities to better simulate ITER plasma antenna loading conditions.

Litaudon, X [CEA, France; Bernard, J. M. [CEA, IRFM, France; Colas, L. [CEA, France; Dumont, R. J. [CEA Cadarache, St. Paul lex Durance, France; Argouarch, A. [CEA Cadarache, St. Paul lex Durance, France; Bottollier-Curtet, H. [CEA, IRFM, France; Bremond, S. [CEA, IRFM, France; Champeaux, S. [CEA, IRFM, France; Corre, Y. [CEA Cadarache, St. Paul lex Durance, France; Dumortier, P. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Firdaouss, M. [CEA, IRFM, France; Guilhem, D. [CEA, IRFM, France; Gunn, J. P. [CEA, IRFM, France; Gouard, Ph. [CEA, DAM, DIF, Arpajon cedex, France; Hoang, G T [CEA, IRFM, France; Jacquot, Jonathan [CEA, IRFM, France; Klepper, C Christopher [ORNL; Kubic, M. [CEA, IRFM, France; Kyrytsya, V. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Lombard, G. [CEA, IRFM, France; Milanesio, D. [Politecnico di Torino; Messiaen, A. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Mollard, P. [CEA, IRFM, France; Meyer, O. [CEA Cadarache, St. Paul lex Durance, France; Zarzoso, D. [CEA, IRFM, France

2013-01-01T23:59:59.000Z

146

The role of heating and current drive in ITER  

SciTech Connect

This report discusses and summarize the role of heating and non-inductive current drive in ITER as: (1) ITER must have heating power sufficient for ignition. (2) The heating system must be capable of current drive. (3) Steady-state operation is an ``ultimate goal.`` It is recognized that additional heating and current drive power (beyond what is initially installed on ITER) may be required. (4) The ``Ultimate goal of steady-state operation`` means steady-state with Q{sub CD} {ge} 5. Unlike the ``Terms of Reference`` for the ITER CDA, the ``ITER Technical Objectives and Approaches`` for the EDA sets no goal for the neutron wall load during steady-state operation. (5) In addition to bulk current drive, the ITER heating and current drive system should be used for current profile control and for burn control.

Nevins, W.M.; Haney, S.

1993-10-18T23:59:59.000Z

147

Kinetic damping of resistive wall modes in ITER  

SciTech Connect

Full drift kinetic modelling including finite orbit width effects has been used to assess the passive stabilisation of the resistive wall mode (RWM) that can be expected in the ITER advanced scenario. At realistic plasma rotation frequency, the thermal ions have a stabilising effect on the RWM, but the stability limit remains below the target plasma pressure to achieve Q = 5. However, the inclusion of damping arising from the fusion-born alpha particles, the NBI ions, and ICRH fast ions extends the RWM stability limit above the target {beta} for the advanced scenario. The fast ion damping arises primarily from finite orbit width effects and is not due to resonance between the particle frequencies and the instability.

Chapman, I. T.; Liu, Y. Q. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Asunta, O. [Department of Applied Physics, Association EURATOM-Tekes, Aalto University, P.O. Box 14100 FI-00076 AALTO (Finland); Graves, J. P. [CRPP, Association EURATOM/Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Johnson, T. [EURATOM-VR Association, EES, KTH, Stockholm (Sweden); Jucker, M. [GFDL/Princeton University, AOS Program, Princeton, New Jersey 08544 (United States)

2012-05-15T23:59:59.000Z

148

Benchmarking ICRF Full-wave Solvers for ITER  

DOE Green Energy (OSTI)

Abstract Benchmarking of full-wave solvers for ICRF simulations is performed using plasma profiles and equilibria obtained from integrated self-consistent modeling predictions of four ITER plasmas. One is for a high performance baseline (5.3 T, 15 MA) DT H-mode. The others are for half-field, half-current plasmas of interest for the pre-activation phase with bulk plasma ion species being either hydrogen or He4. The predicted profiles are used by six full-wave solver groups to simulate the ICRF electromagnetic fields and heating, and by three of these groups to simulate the current-drive. Approximate agreement is achieved for the predicted heating power for the DT and He4 cases. Factor of two disagreements are found for the cases with second harmonic He3 heating in bulk H cases. Approximate agreement is achieved simulating the ICRF current drive.

R. V. Budny, L. Berry, R. Bilato, P. Bonoli, M. Brambilla, R. J. Dumont, A. Fukuyama, R. Harvey, E. F. Jaeger, K. Indireshkumar, E. Lerche, D. McCune, C. K. Phillips, V. Vdovin, J. Wright, and members of the ITPA-IOS

2011-01-06T23:59:59.000Z

149

International Workshop: MFE Roadmapping in the ITER Era | Princeton...  

NLE Websites -- All DOE Office Websites (Extended Search)

Princeton University Princeton, NJ International Workshop: MFE Roadmapping in the ITER Era Princeton University Princeton, NJ Host: G.H. Neilson Coordinator: Pamela Hampton...

150

Progress in the Safety and Licensing of ITER  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

Neill Taylor; Carlos Alejaldre; Pierre Cortes

151

Extrapolation and Local Acceleration of an Iterative Process for ...  

E-Print Network (OSTI)

Apr 19, 2012 ... Abstract: We consider sequential iterative processes for the common fixed point problem of families of cutter operators on a Hilbert space.

152

Port-Based Plasma Diagnostic Infrastructure on ITER  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

C. S. Pitcher et al.

153

Optimization Online - On the use of iterative methods in cubic ...  

E-Print Network (OSTI)

Sep 11, 2013 ... On the use of iterative methods in cubic regularization for unconstrained optimization. Tommaso Bianconcini (tommaso.bianconcini ***at*** ...

154

ITER CS Conductor Helium Inlet Design Optimization and Evaluation  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

R. Leonard Myatt; Nicolai N. Martovetsky; Charlotte Barbier; Kevin D. Freudenberg

155

A synopsis of collective alpha effects and implications for ITER  

SciTech Connect

This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.

Sigmar, D.J.

1990-10-01T23:59:59.000Z

156

President Bush Issues Executive Order Designating ITER International...  

Office of Science (SC) Website

to join counterparts from China, the European Union, India, Japan, the Republic of Korea and the Russian Federation at the organization's first meeting of the ITER Council in...

157

Toward a design for the ITER plasma shape and stability control system  

SciTech Connect

A design strategy for an integrated shaping and stability control algorithm for ITER is described. This strategy exploits the natural multivariable nature of the system so that all poloidal field coils are used to simultaneously control all regulated plasma shape and position parameters. A nonrigid, flux-conserving linearized plasma response model is derived using a variational procedure analogous to the ideal MHD Extended Energy Principle. Initial results are presented for the non-rigid plasma response model approach applied to an example DIII-D equilibrium. For this example, the nonrigid model is found to yield a higher passive growth rate than a rigid current-conserving plasma response model. Multivariable robust controller design methods are discussed and shown to be appropriate for the ITER shape control problem.

Humphreys, D.A.; Leuer, J.A.; Kellman, A.G. [General Atomics, San Diego, CA (United States); Haney, S.W.; Bulmer, R.H.; Pearlstein, L.D. [Lawrence Livermore National Lab., CA (United States); Portone, A. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). ITER Joint Central Team

1994-07-01T23:59:59.000Z

158

An iterative method for single and vertically stacked semiconductor quantum dots simulation  

Science Conference Proceedings (OSTI)

We present in this paper a computational effective nonlinear iterative method for calculating the electron energy spectra in single and vertically stacked InAs/GaAs semiconductor quantum dots. The physical model problem is formulated with the effective ... Keywords: Coupling effect, Electronic structure, Energy spectra, Modelling and simulation, Multishift QR method, Nonlinear eigenvalue problem, Semiconductor nanostructure, Single quantum dot, Vertically stacked quantum dot, Wave function

Yiming Li

2005-10-01T23:59:59.000Z

159

A new iterative approach to solving the transport equation  

E-Print Network (OSTI)

We present a new iterative approach to solving neutral-particle transport problems. The scheme divides the transport solution into its particular and homogeneous or “source-free” components. The particular problem is solved directly, while the homogeneous problem is found iteratively. To organize the iterative inversion of the homogeneous components, we exploit the structures of the so called Case-modes that compose it. The asymptotic Case-modes, those that vary slowly in space and angle, are assigned to a diffusion solver. The remaining transient Case-modes, those with large spatial gradients, are assigned to a transport solver. The scheme iterates on the contribution from each solver until the particular plus homogeneous solution converges. The iterative method is implemented successfully in slab geometry with isotropic scattering and one energy group. The convergence rate of the method is only weakly dependent on the scattering ratio of the problem. Instead, the rate of convergence depends strongly on the material thickness of the slab, with thick slabs converging in few iterations. The transient solution is obtained by applying a One Cell Inversion scheme instead of a Source Iteration based scheme. Thus, the transient unknowns are calculated with little coordination between them. This independence among unknowns makes our scheme ideally suited for transport calculations on parallel architectures. The slab geometry iterative scheme is adapted to XY geometry. Unfortunately, this attempt to extend the slab geometry iterative scheme to multiple dimensions has not been successful. The exact filtering scheme needed to discriminate asymptotic and transient modes has not been obtained and attempts to approximate this filtering process resulted in a divergent iterative scheme. However, the development of this iterative scheme yield valuable analysis tools to understand the Case-mode structure of any spatial discretization under arbitrary material properties.

Maslowski Olivares, Alexander Enrique

2008-12-01T23:59:59.000Z

160

Design, manufacture and initial operation of the beryllium components of the JET ITER-like wall  

E-Print Network (OSTI)

The aim of the JET ITER-like Wall Project was to provide JET with the plasma facing material combination now selected for the DT phase of ITER (bulk beryllium main chamber limiters and a full tungsten divertor) and, in conjunction with the upgraded neutral beam heating system, to achieve ITER relevant conditions. The design of the bulk Be plasma facing components had to be compatible with increased heating power and pulse length, as well as to reuse the existing tile supports originally designed to cope with disruption loads from carbon based tiles and be installed by remote handling. Risk reduction measures (prototypes, jigs, etc) were implemented to maximize efficiency during the shutdown. However, a large number of clashes with existing components not fully captured by the configuration model occurred. Restarting the plasma on the ITER-like Wall proved much easier than for the carbon wall and no deconditioning by disruptions was observed. Disruptions have been more threatening than expected due to the redu...

Riccardo, V; Matthews, G F; Nunes, I; Thompson, V; Villedieu, E; Contributors, JET EFDA

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

ITER, fusion and the power reactor Leonid E. Zakharov,  

E-Print Network (OSTI)

came from outside of the FES "street light spot" when propulsion of lithium was invented as potentially the fusion research in the World. It also should affect the US approach to the reactor. 1 ITER and the basic reactor, it is necessary to realize that the ITER project, although vital for keeping fusion research

Zakharov, Leonid E.

162

Iterated local search for biclustering of microarray data  

Science Conference Proceedings (OSTI)

In the context of microarray data analysis, biclustering aims to identify simultaneously a group of genes that are highly correlated across a group of experimental conditions. This paper presents a Biclustering Iterative Local Search (BILS) algorithm ... Keywords: analysis of DNA microarray data, biclustering, evaluation function, iterative local search

Wassim Ayadi; Mourad Elloumi; Jin-Kao Hao

2010-09-01T23:59:59.000Z

163

Multi-sensor calibration through iterative registration and fusion  

Science Conference Proceedings (OSTI)

In this paper, a new multi-sensor calibration approach, called iterative registration and fusion (IRF), is presented. The key idea of this approach is to use surfaces reconstructed from multiple point clouds to enhance the registration accuracy and robustness. ... Keywords: B-spline surface reconstruction, Iterative closest point (ICP), Kalman filter, Registration, Sensor calibration

Yunbao Huang; Xiaoping Qian; Shiliang Chen

2009-04-01T23:59:59.000Z

164

Key issues in ITER diagnostics: Problems and solutions (invited)  

Science Conference Proceedings (OSTI)

The key problems associated with designing diagnostic systems for the International Thermonuclear Experimental Reactor (ITER) are identified and representative solutions are described. The plans for dealing with some outstanding issues are briefly presented. The detailed work is specific to the ITER

A. E. Costley; Members of the ITER Joint Central Team and Home Teams

1999-01-01T23:59:59.000Z

165

ITER Central Solenoid Coil Insulation Qualification  

Science Conference Proceedings (OSTI)

An insulation system for ITER Central Solenoid must have sufficiently high electrical and structural strength. Design efforts to bring stresses in the turn and layer insulation within allowables failed. It turned out to be impossible to eliminate high local tensile stresses in the winding pack. When high local stresses can not be designed out, the qualification procedure requires verification of the acceptable structural and electrical strength by testing. We built two 4x4 arrays of the conductor jacket with two options of the CS insulation and subjected the arrays to 1.2 million compressive cycles at 60 MPa and at 76 K. Such conditions simulated stresses in the CS insulation. We performed voltage withstand tests and after end of cycling we measured the breakdown voltages between in the arrays. After that we dissectioned the arrays and studied micro cracks in the insulation. We report details of the specimens preparation, test procedures and test results.

Martovetsky, Nicolai N [ORNL; Mann Jr, Thomas Latta [ORNL; Miller, John L [ORNL; Freudenberg, Kevin D [ORNL; Reed, Richard P [Cryogenic Materials, Inc.; Walsh, Robert P [Florida State University; McColskey, J D [National Institute of Standards and Technology (NIST), Boulder; Evans, D [Advanced Cryogenic Materials

2010-01-01T23:59:59.000Z

166

ITER CENTRAL SOLENOID COIL INSULATION QUALIFICATION  

Science Conference Proceedings (OSTI)

An insulation system for ITER Central Solenoid must have sufficiently high electrical and structural strength. Design efforts to bring stresses in the turn and layer insulation within allowables failed. It turned out to be impossible to eliminate high local tensile stresses in the winding pack. When high local stresses can not be designed out, the qualification procedure requires verification of the acceptable structural and electrical strength by testing. We built two 4 x 4 arrays of the conductor jacket with two options of the CS insulation and subjected the arrays to 1.2 million compressive cycles at 60 MPa and at 76 K. Such conditions simulated stresses in the CS insulation. We performed voltage withstand tests and after end of cycling we measured the breakdown voltages between in the arrays. After that we dissectioned the arrays and studied micro cracks in the insulation. We report details of the specimens preparation, test procedures and test results.

Martovetsky, N N; Mann, T L; Miller, J R; Freudenberg, K D; Reed, R P; Walsh, R P; McColskey, J D; Evans, D

2009-06-11T23:59:59.000Z

167

Iterative solutions to large sparse finite element equations  

E-Print Network (OSTI)

Iterative methods are widely used to solve sparse linear systems due to the improvements which can be achieved in reducing the solution time and increasing the size of the problem which can be solved on a given computer compared to traditional direct solvers. The theory behind the convergence rate relationship and storage requirements for the preconditioned conjugate gradient methods using the diagonal scaling, incomplete Cholesky decomposition and SSOR preconditioners is explained in detail in this study. Sparse matrix storage techniques, such as profile, element-by-element, and compact row storage, are described along with the redefined matrix operations for each storage technique which must be used to eliminate the operations on zero elements. A procedure to directly assemble the global stiffness in compact row storage format from element stiffness matrices is introduced. Numerical studies have been performed to compare the storage requirements, the convergence rate, and the solution time for the direct and PCG methods using various storage formats. Effects of different material properties and external loading on the convergence rate and solution time are also analyzed. The test problems for this study are based on the three-dimensional linear elasticity finite element equations. The physical memory of 64 MB of RAM of the IBM RISC/6000 Model 355 workstation was the limiting factor for the size of the sparse linear system that could be solved in this study. The diagonal preconditioned conjugate gradient method with the compact row storage has solved a three-dimensional finite element problem up to a maximum of 50,000 equations on an IBM RISC/6000 Model 355 workstation with 64 MB of RAM. To apply adaptive mesh refinement on certain regions of a coarse mesh, the modeling error over a coarse mesh must be estimated. This thesis will show that the modeling error from an intermediate unconverged coarse mesh solution will closely match the modeling error from the converged solution. This result may lead to quicker solution times for a highly accurate mesh based on adaptive mesh refinement iterative methods.

Wang, Hongbing

1995-01-01T23:59:59.000Z

168

Microsoft Word - Second_ ITER Council Press Release.doc  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Neil Calder Neil Calder Tel: 00 33 (0)6 14 16 41 75 ITER GAINS MOMENTUM Aomori, Japan 18 June 2008 On 17-18 June 2008, the ITER Council, the Governing Body of the new international Organization, convened for its second meeting. The two day meeting in Aomori, Japan, brought together senior representatives from the seven ITER Members: China, the European Union, India, Japan, Korea, Russia and the United States. Mr. Shingo Mimura, Governor of the Aomori Prefecture, welcomed delegates with a reminder of the global significance of the ITER project. "At a time when stable energy supplies and the promotion of strategies to tackle climate change are topics of global concern, the world is watching the ITER project. Implemented by seven parties that together make up half

169

A sequential partly iterative approach for multicomponent reactive transport with CORE2D  

SciTech Connect

CORE{sup 2D} V4 is a finite element code for modeling partly or fully saturated water flow, heat transport and multicomponent reactive solute transport under both local chemical equilibrium and kinetic conditions. It can handle coupled microbial processes and geochemical reactions such as acid-base, aqueous complexation, redox, mineral dissolution/precipitation, gas dissolution/exsolution, ion exchange, sorption via linear and nonlinear isotherms, sorption via surface complexation. Hydraulic parameters may change due to mineral precipitation/dissolution reactions. Coupled transport and chemical equations are solved by using sequential iterative approaches. A sequential partly-iterative approach (SPIA) is presented which improves the accuracy of the traditional sequential noniterative approach (SNIA) and is more efficient than the general sequential iterative approach (SIA). While SNIA leads to a substantial saving of computing time, it introduces numerical errors which are especially large for cation exchange reactions. SPIA improves the efficiency of SIA because the iteration between transport and chemical equations is only performed in nodes with a large mass transfer between solid and liquid phases. The efficiency and accuracy of SPIA are compared to those of SIA and SNIA using synthetic examples and a case study of reactive transport through the Llobregat Delta aquitard in Spain. SPIA is found to be as accurate as SIA while requiring significantly less CPU time. In addition, SPIA is much more accurate than SNIA with only a minor increase in computing time. A further enhancement of the efficiency of SPIA is achieved by improving the efficiency of the Newton-Raphson method used for solving chemical equations. Such an improvement is obtained by working with increments of log-concentrations and ignoring the terms of the Jacobian matrix containing derivatives of activity coefficients. A proof is given for the symmetry and non-singularity of the Jacobian matrix. Numerical analyses performed with synthetic examples confirm that these modifications improve the efficiency and convergence of the iterative algorithm.

Samper, J.; Xu, T.; Yang, C.

2008-11-01T23:59:59.000Z

170

Atomic data for the ITER Core Imaging X-ray Spectrometer  

SciTech Connect

The parameters of the ITER core plasmas will be measured using the Core Imaging X-ray Spectrometer (CIXS), a high-resolution crystal spectrometer focusing on the L-shell spectra of highly ionized tungsten atoms. In order to correctly infer the plasma properties accurate atomic data are required. Here, some aspects of the underlying physics are discussed using experimental data and theoretical predictions from modeling.

Clementson, J; Beiersdorfer, P; Biedermann, C; Bitter, M; Delgado-Aparicio, L F; Graf, A; Gu, M F; Hill, K W; Barnsley, R

2012-06-15T23:59:59.000Z

171

Iterative conformal mapping approach to diffusion-limited aggregation with surface tension effect  

E-Print Network (OSTI)

We present a simple method for incorporating the surface tension effect into an iterative conformal mapping model of two-dimensional diffusion-limited aggregation. A curvature-dependent growth probability is introduced and the curvature is given by utilizing the branch points of a conformal map. The resulting cluster exhibits a crossover from compact to fractal growth. In the fractal growth regime, it is confirmed, by the conformal map technique, that the fractal dimension of its area and perimeter length coincide.

Hiroshi Miki; Haruo Honjo

2013-03-04T23:59:59.000Z

172

Trust and multi-agent systems: applying the "diffuse, default model" of trust to experiments involving artificial agents  

Science Conference Proceedings (OSTI)

We argue that the notion of trust, as it figures in an ethical context, can be illuminated by examining research in artificial intelligence on multi-agent systems in which commitment and trust are modeled. We begin with an analysis of a philosophical ... Keywords: Artificial agents, Default trust, Diffuse trust, Multi-agent systems, Trust

Jeff Buechner; Herman T. Tavani

2011-03-01T23:59:59.000Z

173

Mission of ITER and Challenges for the Young  

Science Conference Proceedings (OSTI)

It is recognized that the ongoing effort to provide sufficient energy for the wellbeing of the globe's population and to power the world economy is of the greatest importance. ITER is a joint international research and development project that aims to demonstrate the scientific and technical feasibility of fusion power. It represents the responsible actions of governments whose countries comprise over half the world's population, to create fusion power as a source of clean, economic, carbon dioxide-free energy. This is the most important science initiative of our time.The partners in the Project--the ITER Parties--are the European Union, Japan, the People's Republic of China, India, the Republic of Korea, the Russian Federation and the USA. ITER will be constructed in Europe, at Cadarache in the South of France. The talk will illustrate the genesis of the ITER Organization, the ongoing work at the Cadarache site and the planned schedule for construction. There will also be an explanation of the unique aspects of international collaboration that have been developed for ITER.Although the present focus of the project is construction activities, ITER is also a major scientific and technological research program, for which the best of the world's intellectual resources is needed. Challenges for the young, imperative for fulfillment of the objective of ITER will be identified. It is important that young students and researchers worldwide recognize the rapid development of the project, and the fundamental issues that must be overcome in ITER.The talk will also cover the exciting career and fellowship opportunities for young people at the ITER Organization.

Ikeda, Kaname [Director General, ITER Organization Cadarache Centre, 13108 St Paul lez Durance (France)

2009-02-19T23:59:59.000Z

174

Conference on iterative methods for large linear systems  

SciTech Connect

This conference is dedicated to providing an overview of the state of the art in the use of iterative methods for solving sparse linear systems with an eye to contributions of the past, present and future. The emphasis is on identifying current and future research directions in the mainstream of modern scientific computing. Recently, the use of iterative methods for solving linear systems has experienced a resurgence of activity as scientists attach extremely complicated three-dimensional problems using vector and parallel supercomputers. Many research advances in the development of iterative methods for high-speed computers over the past forty years are reviewed, as well as focusing on current research.

Kincaid, D.R. [comp.

1988-12-01T23:59:59.000Z

175

Successful Experimental Verification of the Tokamak Exhaust Processing Concept of ITER with the CAPER Facility  

SciTech Connect

One of the design targets for the Tokamak Exhaust Processing (TEP) system of ITER is not to lose more than 10{sup -5}gh{sup -1} into the Normal Vent Detritiation system of the Tritium Plant. The plasma exhaust gas therefore needs to be processed in a way that a tritium removal efficiency of about 10{sup 8} with respect to the flow rate is achieved. Expressed in terms of tritium concentrations this corresponds to a decontamination from about 130 gm{sup -3} down to about 10{sup -4} gm{sup -3} (about 1 Cim{sup -3} = 3.7*10{sup 10} Bqm{sup -3}). The three step reference process for the TEP system of ITER is called CAPER and has been developed and realized at the Tritium Laboratory Karlsruhe (TLK). After the successful commissioning of the PERMCAT reactor as the key component of the third step detailed parametric tritium testing of the 3 steps involving the processing of more than 300 g tritium has been carried out and decontamination factors beyond the design requirements have been demonstrated for each process step and for the process as a whole. Not only the decontamination factor of 10{sup 8} as required by ITER, but also the operational mode of TEP as a waste dump for gases from diverse sources has been experimentally validated with the CAPER facility.

Bornschein, B.; Glugla, M.; Guenther, K.; Le, T.L.; Simon, K.H.; Welte, S. [Forschungszentrum Karlsruhe (Germany)

2005-07-15T23:59:59.000Z

176

Resent Status of ITER Equatorial Launcher Development  

SciTech Connect

The ITER equatorial launcher is divided into a front shield and a port plug. The front shield is composed of fourteen blanket shield modules so as to form three openings for the injection of mm-wave beams into plasma. Twenty-four waveguide transmission lines, internal shields, cooling pipes and so on are installed in the port plug. The transmission lines consist of the corrugated waveguides, miter bends and the free space propagation region utilizing two mirrors in front of the waveguide outlet. The analysis of mm-wave beam propagation in the region shows that the transmission efficiency more than 99.5% is attained. The high power experiments of the launcher mock-up have been carried out and the measured field patterns at each mirror and the outlet of the launcher are agreed with the calculations. It is concluded that the transmission line components in the launcher mock-up are fabricated as designed and the present mm-wave design in the launcher is feasible.

Takahashi, K.; Kajiwara, K.; Kasugai, A.; Oda, Y.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1, Naka Ibaraki, 311-0193 (Japan)

2009-11-26T23:59:59.000Z

177

A Neutronics Shielding Mock-Up Experiment for Reduction of Uncertainty on the Prediction of the ITER-TFC Nuclear Heating  

Science Conference Proceedings (OSTI)

Technical Paper / First Joint ITER-IAEA Technical Meeting on Analysis of ITER Materials and Technologies

M. Angelone; P. Batistoni; F. Moro; M. Pillon; R. Villari; M. Loughlin

178

Experimental vertical stability studies for ITER performance and design  

E-Print Network (OSTI)

Operating experimental devices have provided key inputs to the design process for ITER axisymmetric control. In particular, experiments have quantified controllability and robustness requirements in the presence of realistic ...

Hutchinson, Ian H.

179

United States and International Partners Initial ITER Agreement |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

International Partners Initial ITER Agreement International Partners Initial ITER Agreement United States and International Partners Initial ITER Agreement May 24, 2006 - 10:48am Addthis Paves the Way for Large-Scale, Clean Fusion Energy Project BRUSSELS, BELGIUM - Representing the United States, Dr. Raymond L. Orbach, Director of the U.S. Department of Energy's (DOE) Office of Science, joined counterparts from China, the European Union, India, Japan, the Republic of Korea, and the Russian Federation today to initial an agreement to construct ITER, an international fusion energy project. Fusion energy is an important component of President Bush's Advanced Energy Initiative (AEI), given fusion's potential to become an attractive long-range option for the U.S. clean energy portfolio. In FY 2006, DOE allocated $25

180

Monitoring a multi-agent system evolution through iterative development  

Science Conference Proceedings (OSTI)

Iterative development is a well know project management technique which has notably been popularized in object-oriented development through the use of the Rational Unified Process. Such an approach is nevertheless always driven by milestones rules on ...

Yves Wautelet; Manuel Kolp

2010-09-01T23:59:59.000Z

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181

Accelerating Data Transfers In Iterative MapReduce Bingjing Zhang  

E-Print Network (OSTI)

Words-Iterative MapReduce; Data-intensive applications; Data transfer; Broadcasting; Shuffling; Fat-Tree topology I solvers and basic matrix primitives as the common computing kernels for computer vision, rendering

182

On-the-fly progress detection in iterative stream queries  

Science Conference Proceedings (OSTI)

Multiple researchers have proposed cyclic query plans for evaluating iterative queries over streams or rapidly changing input. The Declarative Networking community uses cyclic plans to evaluate Datalog programs that track reachability and other graph ...

Badrish Chandramouli; Jonathan Goldstein; David Maier

2009-08-01T23:59:59.000Z

183

International Thermonuclear Experimental Reactor (ITER) neutral beam design  

SciTech Connect

This report discusses the following topics on ITER neutral beam design: ion dump; neutralizer and module gas flow analysis; vacuum system; cryogenic system; maintainability; power distribution; and system cost.

Myers, T.J.; Brook, J.W.; Spampinato, P.T.; Mueller, J.P.; Luzzi, T.E.; Sedgley, D.W. (Grumman Corp., Bethpage, NY (USA). Space Systems Div.)

1990-10-01T23:59:59.000Z

184

JET physics in support of ITER: Results and future work  

Science Conference Proceedings (OSTI)

The JET Programme to 1999 concentrates on issues that must be solved before a decision to construct ITER can be taken. The paper discusses three areas representative of the physics support provided: confinement studies

M. Keilhacker; and the JET Team

1995-01-01T23:59:59.000Z

185

Evaluation of graphite/steam interactions for ITER (International Thermonuclear Experimental Reactor)  

DOE Green Energy (OSTI)

In this report we present the results of an experimental/analytical study designed to determine the quantity of hydrogen generated during a coolant inleakage accident in ITER. This hydrogen could represent a potential explosive hazard, provided the proper conditions exist, causing machine damage and release of radioactive material. We have measured graphite/steam reaction rates for several graphites and carbon-based composites at temperatures between 1000 C and 1700 C. The effects of steam flow rate, and partial pressure were also examined. The measured reaction rates correlated well with two Arrhenius type relationships. We have used the relationships for GraphNOL N3M in a thermal model to determine that for ITER the quantity of hydrogen produced would range between 5 and 35 kg, depending upon how the graphite tiles are attached to the first wall. While 5 kg is not a significant concern, 35 kg presents an explosive hazard. 20 refs., 14 figs., 1 tab.

Smolik, G.R.; Merrill, B.J.; Piet, S.J.; Holland, D.F.

1990-09-01T23:59:59.000Z

186

TO APPEAR IN J. VLSI AND SIGNAL PROCESSING (SPRINGER), SPECIAL ISSUE ON UWB 1 An Iterative Algorithm and Low Complexity  

E-Print Network (OSTI)

that our new algorithm operates at lower signal to noise ratio than earlier works using iterative message algorithm. Specifically, the redundant models can be combined together so that memory usage can be reduced of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA

Southern California, University of

187

Development of the ITER magnetic diagnostic set and specification  

SciTech Connect

ITER magnetic diagnostics are now in their detailed design and R and D phase. They have passed their conceptual design reviews and a working diagnostic specification has been prepared aimed at the ITER project requirements. This paper highlights specific design progress, in particular, for the in-vessel coils, steady state sensors, saddle loops and divertor sensors. Key changes in the measurement specifications, and a working concept of software and electronics are also outlined.

Vayakis, G.; Delhom, D.; Encheva, A.; Giacomin, T.; Jones, L.; Patel, K. M.; Portales, M.; Prieto, D.; Simrock, S.; Snipes, J. A.; Udintsev, V. S.; Watts, C.; Winter, A.; Zabeo, L. [ITER Organization, Route de Vinon, F-13115 St Paul lez Durance (France); Arshad, S.; Perez-Lasala, M.; Sartori, F. [Fusion for Energy, Barcelona (Spain)

2012-10-15T23:59:59.000Z

188

An iterative semi-implicit scheme with robust damping  

Science Conference Proceedings (OSTI)

An efficient, iterative semi-implicit (SI) numerical method for the time integration of stiff wave systems is presented. Physics-based assumptions are used to derive a convergent iterative formulation of the SI scheme which enables the monitoring and ... Keywords: 52.30Ex, 52.35Hr, 52.35Py, 52.35Vd, 52.65Tt, Dispersive plasma waves, Gyrofluid, Magnetic reconnection, Robust damping, Semi-implicit methods, Symplectic methods

N. F. Loureiro; G. W. Hammett

2008-04-01T23:59:59.000Z

189

Rayleigh Quotient Iteration in 3D, Deterministic Neutron Transport  

Science Conference Proceedings (OSTI)

Today's "grand challenge" neutron transport problems require 3-D meshes with billions of cells, hundreds of energy groups, and accurate quadratures and scattering expansions. Leadership-class computers provide platforms on which high-fidelity fluxes can be calculated. However, appropriate methods are needed that can use these machines effectively. Such methods must be able to use hundreds of thousands of cores and have good convergence properties. Rayleigh quotient iteration (RQI) is an eigenvalue solver that has been added to the Sn code Denovo to address convergence. Rayleigh quotient iteration is an optimal shifted inverse iteration method that should converge in fewer iterations than the more common power method and other shifted inverse iteration methods for many problems of interest. Denovo's RQI uses a new multigroup Krylov solver for the fixed source solutions inside every iteration that allows parallelization in energy in addition to space and angle. This Krylov solver has been shown to scale successfully to 200,000 cores: for example one test problem scaled from 69,120 cores to 190,080 cores with 98% efficiency. This paper shows that RQI works for some small problems. However, the Krylov method upon which it relies does not always converge because RQI creates ill-conditioned systems. This result leads to the conclusion that preconditioning is needed to allow this method to be applicable to a wider variety of problems.

Slaybaugh, R [University of Wisconsin; Evans, Thomas M [ORNL; Davidson, Gregory G [ORNL; Wilson, P. [University of Wisconsin

2012-01-01T23:59:59.000Z

190

Visible and Infrared Optical Design for the ITER Upper Ports  

SciTech Connect

This document contains the results of an optical design scoping study of visible-light and infrared optics for the ITER upper ports, performed by LLNL under contract for the US ITER Project Office. ITER is an international collaboration to build a large fusion energy tokamak with a goal of demonstrating net fusion power for pulses much longer than the energy confinement time. At the time of this report, six of the ITER upper ports are planned to each to contain a camera system for recording visible and infrared light, as well as other diagnostics. the performance specifications for the temporal and spatial resolution of this system are shown in the Section II, Functional Specifications. They acknowledge a debt to Y. Corre and co-authors of the CEA Cadarache report ''ITER wide-angle viewing and thermographic and visible system''. Several of the concepts used in this design are derived from that CEA report. The infrared spatial resolution for optics of this design is diffraction-limited by the size of the entrance aperture, at lower resolution than listed in the ITER diagnostic specifications. The size of the entrance aperture is a trade-off between spatial resolution, optics size in the port, and the location of relay optics. The signal-to-noise ratio allows operation at the specified time resolutions.

Lasnier, C; Seppala, L; Morris, K; Groth, M; Fenstermacher, M; Allen, S; Synakowski, E; Ortiz, J

2007-03-01T23:59:59.000Z

191

Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials  

E-Print Network (OSTI)

Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials, Russian Federation Abstract Within the framework of the ITER Test Blanket Working Group, the ITER Parties have made several proposals for test blanket modules to be tested in ITER from the first day of H

Abdou, Mohamed

192

DESIGN, ANALYSIS AND TEST CONCEPT FOR PROTOTYPE CRYOLINE OF ITER  

Science Conference Proceedings (OSTI)

The ITER cryo-distribution and cryoline is a part of the in-kind supply for India. The design of the systems is in progress. The topology of torus and neutral beam cryoline is defined as six process pipes along with thermal shield at 80 K and outer vacuum jacket. In order to develop confidence in the concept and to establish the high level of engineering and manufacturing technology, a prototype testing has been proposed. The prototype test will be carried out on 1:1 model in terms of dimension. However, the mass flow rate of the supercritical helium at 4.5 K and gaseous helium at 80 K will be on a 1:10 scale. The prototype cryoline has been designed and analyzed for thermal, structural and hydraulic parameters. The objective of this prototype test is to verify mechanical behavior due to thermal stress and pressure force, thermal and hydraulic performances. The concept of test facility has been realized along with the Piping and Instrumentation (P and I) diagram, instrumentation, controls, data acquisition, 80 K helium generation system along with supply and return valve boxes and interfacing hardware. The design concept, methodology for analysis and results, as well as the test facility have been discussed.

Sarkar, B.; Badgujar, S.; Vaghela, H.; Shah, N.; Bhattacharya, R.; Chakrapani, Ch. [Institute for Plasma Research Bhat, Gandhinagar, Gujarat, 382428 (India)

2008-03-16T23:59:59.000Z

193

Commissioning of the ITER-like ICRF antenna for JET  

Science Conference Proceedings (OSTI)

The new JET ion cyclotron resonance frequency (ICRF) ITER-like antenna (ILA), which was assembled during 2006, was commissioned on the JET RF testbed prior to installation on the JET torus. The 4 resonant double loops (RDL) of the ILA were tested at high power at 42 MHz up to 42 kV for 5 s in 10 min intervals. Low power matching studies using a saltwater load placed in front of the ILA have allowed testing and optimizing proposed matching algorithms on single RDLs, paired RDLs and finally on the full array. The upper limit of the frequency range of the ILA appears to be limited to 47 49 MHz due to the effect on the electrical lengths of the connection between the capacitors and the conjugate T point. Capacitor position scans have allowed obtaining the necessary data to confirm the RF model of the RDL which is necessary for the scattering matrix arc detection. The latter is deemed necessary in order to detect arcs at the low impedance conjugate T of the circuit. The antenna was installed onto JET during August 2007 and commissioning on plasma started May 2008. At present the commissioning of the ILA on JET is ongoing in a series of dedicated experimental campaigns.

Durodie, F. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Dumortier, P. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Huygen, S. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Jachmich, S. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Lerche, E. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Messiaen, A. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Ongena, J. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Van Eester, D. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium; Vervier, M. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Vrancken, M. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Nightingale, M. [EURATOM / UKAEA, Abingdon, UK; Blackman, T. [EURATOM / UKAEA, Abingdon, UK; Edwards, P. [EURATOM / UKAEA, Abingdon, UK; Fanthome, J. [EURATOM / UKAEA, Abingdon, UK; Graham, M. [EURATOM / UKAEA, Abingdon, UK; Jacquet, P. [EURATOM / UKAEA, Abingdon, UK; Kaye, A. [EURATOM / UKAEA, Abingdon, UK; Mayoral, M. -L. [EURATOM / UKAEA, Abingdon, UK; Monakhov, I. [EURATOM / UKAEA, Abingdon, UK; Nicholls, K. [EURATOM / UKAEA, Abingdon, UK; Stork, D. [EURATOM / UKAEA, Abingdon, UK; Walden, A. [EURATOM / UKAEA, Abingdon, UK; Whitehurst, A. [EURATOM / UKAEA, Abingdon, UK; Zastrow, K. -D. [EURATOM / UKAEA, Abingdon, UK; Argouarch, A. [CEA-Cadarache, St. Paul lex Durance, France; Berger-By, G. [CEA-Cadarache, St. Paul lex Durance, France; Loarer, T. [CEA-Cadarache, St. Paul lex Durance, France; Rimini, F. [CEA-Cadarache, St. Paul lex Durance, France; Castano-Giraldo, C. [University of Illinois, Urbana-Champaign; Caughman, John B [ORNL; Goulding, Richard Howell [ORNL; Cocilovo, V. [Association Euratom-ENEA sulla Fusione, Italy; Frigione, D. [Association Euratom-ENEA sulla Fusione, Italy; Sozzi, C. [Association Euratom-ENEA sulla Fusione, Italy; Hobrik, J. [Max-Planck-Institut fu?r Plasmaphysik, EURATOM Association, Garching, Germany; Lamalle, Philippe [ITER Joint Work Site, Cadarache; Nave, M. F. F. [Association EURATOM/IST, Lisbon, Portugal; Tsalas, M. [Association EURATOM-Hellas, Attica, Greece

2009-06-01T23:59:59.000Z

194

Electromagnetic analysis of forces and torques on the baseline and enhanced ITER shield modules due to plasma disruption.  

SciTech Connect

An electromagnetic analysis is performed on the ITER shield modules under different plasma-disruption scenarios using the OPERA-3d software. The models considered include the baseline design as provided by the International Organization and an enhanced design that includes the more realistic geometrical features of a shield module. The modeling procedure is explained, electromagnetic torques are presented, and results of the modeling are discussed.

Kotulski, Joseph Daniel; Coats, Rebecca Sue; Pasik, Michael Francis; Ulrickson, Michael Andrew

2009-08-01T23:59:59.000Z

195

Photonic circuits for iterative decoding of a class of low-density parity-check codes  

E-Print Network (OSTI)

Photonic circuits in which stateful components are coupled via guided electromagnetic fields are natural candidates for native implementation of iterative stochastic algorithms based on propagation of information around a graph. Conversely, such message passing algorithms suggest novel circuit architectures for signal processing and computation that are well matched to nanophotonic device physics. Here we construct and analyze a quantum optical model of a photonic circuit for iterative decoding of a class of low-density parity-check (LDPC) codes called expander codes. Our circuit can be understood as an open quantum system whose autonomous dynamics map straightforwardly onto the subroutines of an LDPC decoding scheme, with several attractive features: it can operate in the ultra-low power regime of photonics in which quantum fluctuations become significant, is robust to noise and component imperfections, achieves comparable performance to known iterative algorithms for this class of codes, and provides an instructive example of how nanophotonic cavity quantum electrodynamic components can enable useful new information technology even if the solid-state qubits on which they are based are heavily dephased and cannot support large-scale entanglement.

Dmitri S. Pavlichin; Hideo Mabuchi

2013-06-03T23:59:59.000Z

196

Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITER  

SciTech Connect

The determination of the fuel ion ratio n{sub t}/n{sub d} in ITER is required at a precision of 20%, time resolution of 100 ms, spatial resolution of a/10, and over a range of 0.01models of ITER to assess the possibility to use neutron emission spectroscopy (NES) for such measurements. We show that NES meets the requirements for ion temperatures T{sub i}>6 keV and for n{sub T}/n{sub D}<0.6. A crucial issue is the signal-to-background situation in the measurement of the weak 2.5 MeV emission from DD reactions in the presence of a background of scattered 14 MeV DT neutrons. Important experimental input and corroboration for this assessment are presented from the time-of-flight neutron spectrometer at JET where the presence of a strong component of backscattered neutrons is observed. Neutron emission components on ITER due to beam-thermal and tritium-tritium reactions can further enhance the prospects for NES.

Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sunden, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M. [Department of Physics and Astronomy, Uppsala University (EURATOM-VR Association), SE-75120 Uppsala (Sweden); Collaboration: JET EFDA Contributors

2010-10-15T23:59:59.000Z

197

President Bush Issues Executive Order Designating ITER International Fusion  

NLE Websites -- All DOE Office Websites (Extended Search)

President President Bush Issues Executive Order Designating ITER International Fusion Energy Organization A Public Interest Organization News Featured Articles Science Headlines 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 Presentations & Testimony News Archives Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 11.19.07 President Bush Issues Executive Order Designating ITER International Fusion Energy Organization A Public Interest Organization Print Text Size: A A A Subscribe FeedbackShare Page November 19, 2007 The White House today announced that President Bush has issued an Executive Order designating the ITER International Fusion Energy Organization as a public international organization. For the purposes of the International

198

Twice-iterated boson-exchange scattering amplitudes  

E-Print Network (OSTI)

We calculate at two-loop order the complex-valued scattering amplitude related to the twice-iterated scalar-isovector boson-exchange between nucleons. In comparison to the once-iterated boson-exchange amplitude it shows less dependence on the scattering angle. We calculate also the iteration of the (static) irreducible one-loop potential with the one-boson exchange and find similar features. Together with the irreducible three-boson exchange potentials and the two-boson exchange potentials with vertex corrections, which are also evaluated analytically, our results comprise all nonrelativistic contributions from scalar-isovector boson-exchange at one- and two-loop order. The applied methods can be straightforwardly adopted to the pseudoscalar pion with its spin- and momentum-dependent couplings to the nucleon.

N. Kaiser

2006-06-12T23:59:59.000Z

199

Experimental and Model Validation of ITER Operational Scenarios  

E-Print Network (OSTI)

Bull. Am. Phys. Soc. 53, 202 (2008)50th American Physical Society Annual Meeting of Division of Plasma Physics Dallas Texas, US, 2008999615345

Casper, T.A.

2008-08-18T23:59:59.000Z

200

Model-Based Iterative Reconstruction for Multimodal Electron ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2014 TMS Annual Meeting & Exhibition. Symposium , Data Analytics for Materials Science and Manufacturing. Presentation Title ...

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Diagnostics of the ITER neutral beam test facility  

SciTech Connect

The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H{sup -}/D{sup -} production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

Pasqualotto, R.; Serianni, G.; Agostini, M.; Brombin, M.; Dalla Palma, M.; Gazza, E.; Pomaro, N.; Rizzolo, A.; Spolaore, M.; Zaniol, B. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Sonato, P.; De Muri, M. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University (Italy); Croci, G. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); Gorini, G. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); CNISM, Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, Milano (Italy)

2012-02-15T23:59:59.000Z

202

Iterated Differential Forms IV: C-Spectral Sequence  

E-Print Network (OSTI)

For the multiple differential algebra of iterated differential forms (see math.DG/0605113 and math.DG/0609287) on a diffiety (O,C) an analogue of C-spectral sequence is constructed. The first term of it is naturally interpreted as the algebra of secondary iterated differential forms on (O,C). This allows to develop secondary tensor analysis on generic diffieties, some simplest elements of which are sketched here. The presented here general theory will be specified to infinite jet spaces and infinitely prolonged PDEs in subsequent notes.

A. M. Vinogradov; L. Vitagliano

2006-10-30T23:59:59.000Z

203

Bragg x-ray survey spectrometer for ITER  

Science Conference Proceedings (OSTI)

Several potential impurity ions in the ITER plasmas will lead to loss of confined energy through line and continuum emission. For real time monitoring of impurities, a seven channel Bragg x-ray spectrometer (XRCS survey) is considered. This paper presents design and analysis of the spectrometer, including x-ray tracing by the Shadow-XOP code, sensitivity calculations for reference H-mode plasma and neutronics assessment. The XRCS survey performance analysis shows that the ITER measurement requirements of impurity monitoring in 10 ms integration time at the minimum levels for low-Z to high-Z impurity ions can largely be met.

Varshney, S. K.; Jakhar, S. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India); Barnsley, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); O'Mullane, M. G. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-10-15T23:59:59.000Z

204

Abstract: Critical Region Vapor-Liquid Equilibrium Model of ...  

Science Conference Proceedings (OSTI)

Two distinct thermodynamic models, the modified Leung-Griffiths (MLG) model ... three iterations, the two correlations are in basic agreement except ...

205

Perturbation Resilience and Superiorization of Iterative Algorithms  

E-Print Network (OSTI)

E-mail: 1yair@math.haifa.ac.il ... significant real-world problems are modeled by constraints that force the sought-after ... world applications, is computational.

206

Overview of Recent Developments in Pellet Injection for ITER  

Science Conference Proceedings (OSTI)

Pellet injection is the primary fueling technique planned for core fueling of ITER burning plasmas. Also, the injection of relatively small pellets to purposely trigger rapid small edge localized modes (ELMs) has been proposed as a possible solution to the heat flux damage from larger natural ELMs likely to be an issue on the ITER divertor surfaces. The ITER pellet injection system is designed to inject pellets into the plasma through both inner and outer wall guide tubes. The inner wall guide tubes will provide high throughput pellet fueling while the outerwall guide tubes will be used primarily to trigger ELMs at a high frequency (>15 Hz). The pellet fueling rate ofeach injector is to be up to 120 Pa-m3/s, which will require the formation of solid D-T at a volumetric rate of ~1500 mm3/s. Two injectors are to be provided for ITER at the startup with a provision for up to six injectorsduring the D-T phase. The required throughput of each injector is greater than that of any injector built to date, and a novel twin-screw continuous extrusion system is being developed to meet the challenging design parameters. Status of the development activities will be presented, highlighting recent progress.

Combs, Stephen Kirk [ORNL; Baylor, Larry R [ORNL; Meitner, Steven J [ORNL; Caughman, John B [ORNL; Rasmussen, David A [ORNL; Maruyama, So [ITER Organization, Cadarache, France

2012-01-01T23:59:59.000Z

207

PTRANSP Tests of TGLF and Predictions for ITER  

SciTech Connect

A new numerical solver for stiff transport predictions has been developed and implemented in the PTRANSP predictive transport code. The TGLF and GLF23 predictive codes have been incorporated in the solver, verified by comparisons with predictions from the XPTOR code, and validated by comparing predicted and measured profiles. Predictions for ITER baseline plasmas are presented.

Robert V. Budny, Xingqiu Yuan, S. Jardin, G. Hammett, G. Staebler, J. Kinsey, members of the ITPA Transport and Confinement Topical Group, and JET EFDA Contributors

2012-09-23T23:59:59.000Z

208

Active spectroscopic measurements using the ITER diagnostic system  

SciTech Connect

Active (beam-based) spectroscopic measurements are intended to provide a number of crucial parameters for the ITER device being built in Cadarache, France. These measurements include the determination of impurity ion temperatures, absolute densities, and velocity profiles, as well as the determination of the plasma current density profile. Because ITER will be the first experiment to study long timescale ({approx}1 h) fusion burn plasmas, of particular interest is the ability to study the profile of the thermalized helium ash resulting from the slowing down and confinement of the fusion alphas. These measurements will utilize both the 1 MeV heating neutral beams and a dedicated 100 keV hydrogen diagnostic neutral beam. A number of separate instruments are being designed and built by several of the ITER partners to meet the different spectroscopic measurement needs and to provide the maximum physics information. In this paper, we describe the planned measurements, the intended diagnostic ensemble, and we will discuss specific physics and engineering challenges for these measurements in ITER.

Thomas, D. M. [ITER Organization, 13067 St. Paul-lez-Durance Cedex (France); Counsell, G. [Fusion for Energy, 08019 Barcelona (Spain); Johnson, D. [US ITER Project Office, Oak Ridge, Tennessee 37830 (United States); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Zvonkov, A. [Russian Research Center ''Kurchatov Institute'', Moscow 123182 (Russian Federation)

2010-10-15T23:59:59.000Z

209

Iterative maximum-likelihood reconstruction in quantum homodyne tomography  

E-Print Network (OSTI)

I propose an iterative expectation maximization algorithm for reconstructing a quantum optical ensemble from a set of balanced homodyne measurements performed on an optical state. The algorithm applies directly to the acquired data, bypassing the intermediate step of calculating marginal distributions. The advantages of the new method are made manifest by comparing it with the traditional inverse Radon transformation technique.

A. I. Lvovsky

2003-11-14T23:59:59.000Z

210

Image segmentation by iterated region merging with localized graph cuts  

Science Conference Proceedings (OSTI)

This paper presents an iterated region merging-based graph cuts algorithm which is a novel extension of the standard graph cuts algorithm. Graph cuts addresses segmentation in an optimization framework and finds a globally optimal solution to a wide ... Keywords: Graph cuts, Image segmentation, Region merging

Bo Peng; Lei Zhang; David Zhang; Jian Yang

2011-10-01T23:59:59.000Z

211

Object oriented parallelisation of graph algorithms using parallel iterator  

Science Conference Proceedings (OSTI)

Multi-core machines are becoming widely used which, as a consequence, forces parallel computing to move from research labs to being adopted everywhere. Due to the fact that developing parallel code is a significantly complex process, the main focus of ... Keywords: graph algorithms, object oriented parallelisation, parallel computing, parallel iterator

Lama Akeila; Oliver Sinnen; Wafaa Humadi

2010-01-01T23:59:59.000Z

212

Robust measurement of ocular torsion using iterative Lucas-Kanade  

Science Conference Proceedings (OSTI)

We present a new method to measure ocular torsion using Lucas-Kanade method. After pixels of iris annulus around a pupil have been converted into Cartesian coordinates, 30 features on the iris was selected then the features were tracked using the iterative ... Keywords: Eye tracking, Lucas-Kanade, Ocular torsion

InBum Lee; ByungHun Choi; Kwang Suk Park

2007-03-01T23:59:59.000Z

213

ITER:The Future International Burning Plasma Experiment Present Status  

E-Print Network (OSTI)

at the time of procurement. #12;ITER27/4/01 Design - In-vessel Remote Handling (1) Systems near the plasma will become radioactive and will require remote maintenance, with special remote handling equipment. In27/4/01 Design - In-vessel Remote Handling (2) Comprehensive R&D has successfully demonstrated

214

SULTAN measurement and qualification: ITER-US-LLNL-NMARTOVETSKY- 092008  

SciTech Connect

Measuring the characteristics of full scale ITER CICC at SULTAN is the critical qualification test. If volt-ampere characteristic (VAC) or volt-temperature characteristic (VTC) are distorted, the criterion of 10 uV/m may not be a valid criterion to judge the conductor performance. Only measurements with a clear absence or low signals from the current distribution should be considered as quantitatively representative, although in some obvious circumstances one can judge if a conductor will meet or fail ITER requirements. SULTAN full scale ITER CICC testing should be done with all measures taken to ensure uniform current redistribution. A full removal of Cr plating in the joint area and complete solder filling of the joints (with provision of the central channel for helium flow) should be mandatory for DC qualification samples for ITER. Also, T and I should be increased slowly that an equilibrium could be established for accurate measurement of Tcs, Ic and N. It is also desirable to go up in down in current and/or temperature (within stable range) to make sure that the equilibrium is reached.

Martovetsky, N N

2006-09-21T23:59:59.000Z

215

Iterative improvement to solve the parcel hub scheduling problem  

Science Conference Proceedings (OSTI)

This paper presents iterative improvement algorithms to solve the parcel hub scheduling problem (PHSP). The PHSP is combinatorial optimization problem that consists of scheduling a set of inbound trailers to a small number of unload docks. At the unload ... Keywords: Cross docks, Genetic algorithms, Local search, Parcel delivery industry, Simulated annealing

Douglas L. McWilliams

2010-08-01T23:59:59.000Z

216

US Plans and Strategy for ITER Blanket Testing  

E-Print Network (OSTI)

per 1000MW fusion power per year Production & Cost · CANDU Reactors: 27 kg from over 40 years, $30MOntario(OPG)TritiumInventory(kg) CANDU Supply w/o Fusion ITER-FEAT (2004 start) 1000 MW Fusion, 10% Avail, TBR 0.0 #12;

California at Los Angeles, University of

217

Optimization-based iterative learning for precise quadrocopter trajectory tracking  

Science Conference Proceedings (OSTI)

Current control systems regulate the behavior of dynamic systems by reacting to noise and unexpected disturbances as they occur. To improve the performance of such control systems, experience from iterative executions can be used to anticipate recurring ... Keywords: Aerial robotics, Convex optimization, Input and state constraints, Kalman filtering, Learning, Motion planning and control, Quadrocopter control, Trajectory tracking

Angela P. Schoellig; Fabian L. Mueller; Raffaello D'Andrea

2012-08-01T23:59:59.000Z

218

Advanced tokamak operating modes in TPX and ITER  

SciTech Connect

A program is described to develop the advanced tokamak physics required for an economic steady-state fusion reactor on existing (short-pulse) tokamak experiments; to extend these operating modes to long-pulse on TPX; and finally to demonstrate them in a long-pulse D-T plasma on ITER.

Nevins, W.M.

1994-12-31T23:59:59.000Z

219

Iterative methods for visualization of implicit surfaces on GPU  

Science Conference Proceedings (OSTI)

The ray-casting of implicit surfaces on GPU has been explored in the last few years. However, until recently, they were restricted to second degree (quadrics). We present an iterative solution to ray cast cubics and quartics on GPU. Our solution targets ...

Rodrigo de Toledo; Bruno Levy; Jean-Claude Paul

2007-11-01T23:59:59.000Z

220

Iterative aperture mask design in phase space using a rank constraint  

E-Print Network (OSTI)

We present an iterative camera aperture design procedure, which determines an optimal mask pattern based on a sparse set of desired intensity distributions at different focal depths. This iterative method uses the ambiguity ...

Horstmeyer, Roarke William

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Reachability analysis of nonlinear analog circuits through iterative reachable set reduction  

Science Conference Proceedings (OSTI)

We propose a methodology for reachability analysis of nonlinear analog circuits to verify safety properties. Our iterative reachable set reduction algorithm initially considers the entire state space as reachable. Our algorithm iteratively determines ...

Seyed Nematollah Ahmadyan, Shobha Vasudevan

2013-03-01T23:59:59.000Z

222

Combining GA and iterative MVDR for DOA estimation in space-time CDMA systems  

Science Conference Proceedings (OSTI)

This paper deals with direction-of-arrival (DOA) estimation of minimum variance distortionless response (MVDR) approach based on iterative searching technique for space-time code-division multiple access (CDMA) systems. It has been shown that the iterative ...

Jhih-Chung Chang

2012-11-01T23:59:59.000Z

223

Energy and particle confinement in ITER (International Thermonuclear Experimental Reactor)  

SciTech Connect

ITER will require a level of energy ({tau}{sub E}) and particle ({tau}{sub p}) confinement sufficient for reaching ignition and extended burn of DT plasmas, with steady-state, high-Q (Q = P{sub fusion}/P{sub aux} = 5P{sub {alpha}}/P{sub aux}) operation as an ultimate goal. This translates into a required confinement capability of T{sub i}(0)n{sub DT}(0){tau}{sub E} {approximately}4--8 {times} 10{sup 21} keV{center dot}s/m{sup 3} for Q {approximately}5--{infinity} (where T{sub i}(0) is the central ion temperature, n{sub DT}(0) is the central DT fuel ion density, {tau}{sub E} is the global energy confinement time). In addition, {tau}{sub p} {sup He}/{tau}{sub E} < 10 is required to ensure that the thermal {alpha}-particle (He) accumulation (n{sub He}/n{sub e}) is less than 10% (where {tau}{sub p}{sup He} is the global thermal alpha particle containment time). Furthermore, the tritium fuel burnup fraction under nominal burn conditions must be greater than 1.5%. While the ITER Tn{tau}{sub E} requirement is about ten times the highest value achieved in JET (3), the extrapolation in plasma physics parameters is less. If {beta} (ratio of plasma kinetic pressure to magnetic pressure), {nu}* (collisionality), and {rho}/a (ratio of the ion gyroradius to the plasma minor radius) are taken as the relevant dimensionless parameters to characterize the plasma, the extrapolation from present JET performance to ITER is a factor {le}2. The ITER concept is based on the expectation that H-mode confinement can be achieved for long pulse. This paper covers the energy and particle confinement issues for ITER. 15 refs.

Uckan, N.A. (Oak Ridge National Lab., TN (USA)); Yushmanov, P.N.; Mukhovatov, V.S.; Parail, V.V.; Putvinskii, S. (Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow (USSR). Inst. Atomnoj Ehnergii); Takizuka, T.; Tsunematsu, T.; Yoshino, R. (Japan Atomic Energy Research Inst., Tokyo (Japan)); Borrass, K.; Engelmann, F.; Kardaun, O.; Lackner, K. (Max-Planck-Institut fuer Plasmaphysik,

1990-01-01T23:59:59.000Z

224

Thermomechanical Performance of the EU TBMs Under a Typical ITER Transient  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

F. Cismondi; G. Aiello; S. Kecskes; G. Rampal

225

Thermomechanical Analysis of the Revised U.S. ITER DCLL Test Blanket Module  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Aaron T. Aoyama; Shahram Sharafat; Nasr Ghoniem; Mohamad Dagher; Clement Wong

226

RAMI Analysis for Designing and Optimizing ITER Tokamak Cooling Water System  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

J. J. Ferrada; W. T. Reiersen

227

Critical Design Issues of the Tokamak Cooling Water System of ITER's Fusion Reactor  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Seokho H. Kim; Jeanette B. Berry

228

High Heat Flux Test of the KO Standard Mockups for ITER First Wall Semi-Prototype  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Suk-Kwon Kim et al.

229

U.S ITER : electromagnetic analysis of transient forces due to disrupted plasma currents on the ITER shield modules.  

SciTech Connect

This paper describes the electromagnetic analysis that has been completed using the OPERA-3d product to characterize the forces on the ITER shield modules as part of the conceptual design. These forces exist due to the interaction of the eddy currents induced in the shield modules and the large magnetic fields present in the tokamak.

Kotulski, Joseph Daniel; Coats, Rebecca Sue; Pasik, Michael Francis

2007-06-01T23:59:59.000Z

230

Home National Sports Business World Features Columns Editorial Japan has key role in ITER project  

E-Print Network (OSTI)

the Congress concerning the United States' share of the costs of the ITER project. The United States quit project The Yomiuri Shimbun The dispute over which nation should host the world's first nuclear fusion, using the ITER project as a basis for achieving the goal. The ITER would be a gigantic facility

231

On HSS and AHSS iteration methods for nonsymmetric positive definite Toeplitz systems  

Science Conference Proceedings (OSTI)

Two iteration methods are proposed to solve real nonsymmetric positive definite Toeplitz systems of linear equations. These methods are based on Hermitian and skew-Hermitian splitting (HSS) and accelerated Hermitian and skew-Hermitian splitting (AHSS). ... Keywords: 65F10, 65F50, AHSS iteration method, Centrosymmetric matrix, HSS iteration method, Skew-centrosymmetric matrix, Toeplitz matrix

Fang Chen; Yao-Lin Jiang

2010-08-01T23:59:59.000Z

232

A Combined Adaptive Law for Fuzzy Iterative Learning Control of Nonlinear Systems With Varying Control Tasks  

Science Conference Proceedings (OSTI)

To deal with the iterative control of uncertain nonlinear systems with varying control tasks, nonzero initial resetting state errors, and nonrepeatable mismatched input disturbance, a new adaptive fuzzy iterative learning controller is proposed in this ... Keywords: Adaptive control, fuzzy system, iterative learning control (ILC), nonlinear systems

Chiang-Ju Chien

2008-02-01T23:59:59.000Z

233

Bi-parameter incremental unknowns ADI iterative methods for elliptic problems  

Science Conference Proceedings (OSTI)

Bi-parameter incremental unknowns (IU) alternating directional implicit (ADI) iterative methods are proposed for solving elliptic problems. Condition numbers of the coefficient matrices for these iterative schemes are carefully estimated. Theoretical ... Keywords: Bi-parameter ADI iterative method, Condition number, Convergence analysis, Incremental unknowns

Aili Yang; Yujiang Wu; Yongqing Wu; Dawei Ren

2012-07-01T23:59:59.000Z

234

Basis functions and parameter optimisation in high-order iterative learning control  

Science Conference Proceedings (OSTI)

In this paper a new parameter-optimal high-order Iterative Learning Control (ILC) algorithms is proposed to extend the work of Owens and Feng [Parameter optimisation in iterative learning control. International Journal of Control 14(11), 1059-1069]. ... Keywords: Basis functions, Iterative learning control, Parameter optimisation

J. HäTöNen; D. H. Owens; K. Feng

2006-02-01T23:59:59.000Z

235

Two-step modulus-based matrix splitting iteration method for linear complementarity problems  

Science Conference Proceedings (OSTI)

Bai has recently presented a modulus-based matrix splitting iteration method, which is a powerful alternative for solving the large sparse linear complementarity problems. In this paper, we further present a two-step modulus-based matrix splitting iteration ... Keywords: Convergence, Iteration method, Linear complementarity problem, Matrix splitting

Li-Li Zhang

2011-05-01T23:59:59.000Z

236

Modulus-based synchronous two-stage multisplitting iteration methods for linear complementarity problems  

Science Conference Proceedings (OSTI)

In order to solve large sparse linear complementarity problems on parallel multiprocessor systems, we construct modulus-based synchronous two-stage multisplitting iteration methods based on two-stage multisplittings of the system matrices. These iteration ... Keywords: Convergence, Linear complementarity problem, Matrix multisplitting, Modulus method, Successive relaxation, Two-stage iteration

Zhong-Zhi Bai; Li-Li Zhang

2013-01-01T23:59:59.000Z

237

Iterative inverse kinematics with manipulator configuration control  

Science Conference Proceedings (OSTI)

A new method, termed the offset modification method (OM method), for solving the manipulator inverse kinematics problem is presented. The OM method works by modifying the link offset values of a manipulator until it is possible to derive closed-form inverse kinematics equations for the resulting manipulator (termed the model manipulator). This procedure allows one to derive a set of three nonlinear equations in three unknowns that, when numerically solved, give an inverse kinematics solution for the original manipulator. The OM method can be applied to manipulators with any number of degrees of freedom, as long as the manipulator satisfies a given set of conditions (Theorem 1). The OM method is tested on a 6-degree-of-freedom manipulator that has no known closed-form inverse kinematics equations. It is shown that the OM method is applicable to real-time manipulator control, can be used to guarantee convergence to a desired endpoint position and orientation (if it exists), and allows one to directly choose which inverse kinematics solution the algorithm will converge to (as specified in the model manipulator closed-form inverse kinematics equations). Applications of the method to other 6-DOF manipulator geometries and to redundant manipulators (i.e. greater than 6 DOF geometries) are discussed.

Grudic, G.Z.; Lawrence, P.D. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Electrical Engineering] [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Electrical Engineering

1993-08-01T23:59:59.000Z

238

An alpha particle measurement system using an energetic neutral helium beam in ITER (invited)  

Science Conference Proceedings (OSTI)

An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He{sup +} ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He{sup +} ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O. [Graduate school of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Shinto, K. [IFMIF R and D Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

2012-02-15T23:59:59.000Z

239

An iterative method to compute the overlap Dirac operator at nonzero chemical potential  

E-Print Network (OSTI)

The overlap Dirac operator at nonzero quark chemical potential involves the computation of the sign function of a non-Hermitian matrix. In this talk we present an iterative method, first proposed by us in Ref. [1], which allows for an efficient computation of the operator, even on large lattices. The starting point is a Krylov subspace approximation, based on the Arnoldi algorithm, for the evaluation of a generic matrix function. The efficiency of this method is spoiled when the matrix has eigenvalues close to a function discontinuity. To cure this, a small number of critical eigenvectors are added to the Krylov subspace, and two different deflation schemes are proposed in this augmented subspace. The ensuing method is then applied to the sign function of the overlap Dirac operator, for two different lattice sizes. The sign function has a discontinuity along the imaginary axis, and the numerical results show how deflation dramatically improves the efficiency of the method.

Jacques Bloch; Andreas Frommer; Bruno Lang; Tilo Wettig

2007-10-01T23:59:59.000Z

240

Qualification of the Joints for ITER Central Solenoid  

SciTech Connect

The ITER Central Solenoid has 36 interpancake joints, 12 bus joints, and 12 feeder joints in the magnet. The joints are required to have resistance below 4 nOhm at 45 kA at 4.5 K. The US ITER Project Office developed two different types of interpancake joints with some variations in details in order to find a better design, qualify the joints, and establish a fabrication process. We built and tested four samples of the sintered joints and two samples with butt-bonded joints (a total of eight joints). Both designs met the specifications. Results of the joint development, test results, and selection of the baseline design are presented and discussed in the paper.

Martovetsky, Nicolai N [ORNL; Berryhill, Adam B [Cryomagnetics, Inc.; Kenney, Steven J [ORNL

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Engineering and manufacturing of ITER first mirror mock-ups  

SciTech Connect

Most of the ITER optical diagnostics aiming at viewing and monitoring plasma facing components will use in-vessel metallic mirrors. These mirrors will be exposed to a severe plasma environment and lead to an important tradeoff on their design and manufacturing. As a consequence, investigations are carried out on diagnostic mirrors toward the development of optimal and reliable solutions. The goals are to assess the manufacturing feasibility of the mirror coatings, evaluate the manufacturing capability and associated performances for the mirrors cooling and polishing, and finally determine the costs and delivery time of the first prototypes with a diameter of 200 and 500 mm. Three kinds of ITER candidate mock-ups are being designed and manufactured: rhodium films on stainless steel substrate, molybdenum on TZM substrate, and silver films on stainless steel substrate. The status of the project is presented in this paper.

Joanny, M.; Travere, J. M.; Salasca, S.; Corre, Y. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Marot, L. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Thellier, C.; Gallay, G.; Cammarata, C.; Passier, B.; Ferme, J. J. [SESO, 305 Rue Louis Armand CS 30504, 13593 Aix-en-Provence Cedex 3 (France)

2010-10-15T23:59:59.000Z

242

Iterative Entanglement Distillation: Approaching full Elimination of Decoherence  

E-Print Network (OSTI)

The distribution and processing of quantum entanglement form the basis of quantum communication and quantum computing. The realization of the two is difficult because quantum information inherently has a high susceptibility to decoherence, i.e. to uncontrollable information loss to the environment. For entanglement distribution, a proposed solution to this problem is capable of fully eliminating decoherence; namely iterative entanglement distillation. This approach builds on a large number of distillation steps each of which extracts a number of weakly decohered entangled states from a larger number of strongly decohered states. Here, for the first time, we experimentally demonstrate iterative distillation of entanglement. Already distilled entangled states were further improved in a second distillation step and also made available for subsequent steps.Our experiment displays the realization of the building blocks required for an entanglement distillation scheme that can fully eliminate decoherence.

Boris Hage; Aiko Samblowski; James DiGuglielmo; Jaromír Fiurášek; Roman Schnabel

2010-07-09T23:59:59.000Z

243

US ITER is a strong contributor in plan to enhance international sharing of  

NLE Websites -- All DOE Office Websites (Extended Search)

US ITER is a strong contributor in plan to enhance international sharing of US ITER is a strong contributor in plan to enhance international sharing of prime ITER real estate By Lynne Degitz, US ITER March 28, 2013 Tweet Widget Facebook Like Google Plus One PPPL's Russell Feder, left, and David Johnson developed key features for a modular approach to housing the extensive diagnostic systems that will be installed on the ITER tokamak. (Photo by Elle Starkman/PPPL Office of Communications) PPPL's Russell Feder, left, and David Johnson developed key features for a modular approach to housing the extensive diagnostic systems that will be installed on the ITER tokamak. Gallery: Diagram of an equatorial port plug shows the three vertical diagnostic shield modules with detachable first wall blocks. The modular approach has many advantages including efficient design collaboration, easier maintenance and the possibility for future upgrades to the ITER diagnostic systems.

244

An Iterative, Dynamically Stabilized(IDS) Method of Data Unfolding  

E-Print Network (OSTI)

We describe an iterative unfolding method for experimental data, making use of a regularization function. The use of this function allows one to build an improved normalization procedure for Monte Carlo spectra, unbiased by the presence of possible new structures in data. We unfold, in a dynamically stable way, data spectra which can be strongly affected by fluctuations in the background subtraction and simultaneously reconstruct structures which were not initially simulated.

Bogdan Malaescu

2011-06-15T23:59:59.000Z

245

Iterative procedure for computing accessible information in quantum communication  

E-Print Network (OSTI)

We present an iterative algorithm that finds the optimal measurement for extracting the accessible information in any quantum communication scenario. The maximization is achieved by a steepest-ascent approach toward the extremal point, following the gradient uphill in sufficiently small steps. We apply it to a simple ad-hoc example, as well as to a problem with a bearing on the security of a tomographic protocol for quantum key distribution.

Jaroslav ?ehá?ek; Berthold-Georg Englert; Dagomir Kaszlikowski

2004-08-20T23:59:59.000Z

246

Progress on the heating and current drive systems for ITER  

SciTech Connect

The electron cyclotron (EC), ion cyclotron (IC), heating-neutral beam (H-NB) and, although not in the day 1 baseline, lower hybrid (LH) systems intended for ITER have been reviewed in 2007/2008 in light of progress of physics and technology in the field. Although the overall specifications are unchanged, notable changes have been approved. Firstly, it has been emphasized that the H&CD systems are vital for the ITER programme. Consequently, the full 73 MW should be commissioned and available on a routine basis before the D/T phase. Secondly, significant changes have been approved at system level, most notably: the possibility to operate the heating beams at full power during the hydrogen phase requiring new shine through protection; the possibility to operate IC with 2 antennas with increased robustness (no moving parts); the possible increase to 2 MW of key components of the EC transmission systems in order to provide an easier upgrading of the EC power as may be required by the project; the addition of a building dedicated to the RF power sources and to a testing facility for acceptance of diagnostics and heating port plugs. Thirdly, the need of a plan for developing, in time for the active phase, a CD system such as LH suitable for very long pulse operation of ITER was recognised. The review describes these changes and their rationale.

Jacquinot, J. [CEA, Cadarache, France; Beaumont, Bertrand [ITER Joint Work Site, Cadarache; Bora, D. [ITER Joint Work Site, Cadarache; Campbell, D. [ITER Joint Work Site, Cadarache; Darbos, Caroline [ITER Joint Work Site, Cadarache; Decamps, H. [ITER Organization, Saint Paul Lez Durance, France; Graceffa, J. [ITER Joint Work Site, Cadarache; Gassmann, T. [ITER Joint Work Site, Cadarache; Hemsworth, R. [ITER Joint Work Site, Cadarache; Henderson, Mark [ITER Joint Work Site, Cadarache; Kobayashi, N. [ITER Joint Work Site, Cadarache; Lamalle, Philippe [ITER Joint Work Site, Cadarache; Schunke, B. [ITER Joint Work Site, Cadarache; Tanaka, M. [ITER Joint Work Site, Cadarache; Tanga, A. [ITER Joint Work Site, Cadarache; Albajar, F. [Fusion for Energy (F4E), Barcelona, Spain; Bonicelli, T. [Fusion for Energy (F4E), Barcelona, Spain; Saibene, G. [Fusion for Energy (F4E), Barcelona, Spain; Sartori, R. [Fusion for Energy (F4E), Barcelona, Spain; Becoulet, A. [CEA, Cadarache, France; Hoang, G. T. [CEA, Cadarache, France; Inoue, T. [Japan Atomic Energy Agency (JAEA), Naka; Sakamoto, K. [Japan Atomic Energy Agency (JAEA), Naka; Takahashi, K. [Japan Atomic Energy Agency (JAEA), Naka; Watanabe, K. [Japan Atomic Energy Agency (JAEA), Naka; Goulding, Richard Howell [ORNL; Rasmussen, David A [ORNL; Swain, David W [ORNL; Chakraborty, A. [ITER India - Bhat, Gandhinagar, Gujarat; Mukherjee, A. [ITER India - Bhat, Gandhinagar, Gujarat; Rao, S. L. [ITER India - Bhat, Gandhinagar, Gujarat; Denisov, G. [Russian Academy of Science, Novgorod, Russia; Nightingale, M. [EURATOM / UKAEA, Abingdon, UK; Sonato, P. [EURATOM / ENEA, Italy

2009-06-01T23:59:59.000Z

247

Iterated amplitudes in the high-energy limit  

E-Print Network (OSTI)

We consider the high-energy limits of the colour ordered four-, five- and six-gluon MHV amplitudes of the maximally supersymmetric QCD in the multi-Regge kinematics where all the gluons are strongly ordered in rapidity. We show that various building blocks occurring in the Regge factorisation (the Regge trajectory, the coefficient functions and the Lipatov vertex) satisfy an iterative structure very similar to the Bern-Dixon-Smirnov (BDS) ansatz. This iterative structure, combined with the universality of the building blocks, enables us to show that in the Euclidean region any two- and three-loop amplitude in multi-Regge kinematics is guaranteed to satisfy the BDS ansatz. We also consider slightly more general kinematics where the strong rapidity ordering applies to all the gluons except the two with either the largest or smallest rapidities, and we derive the iterative formula for the associated coefficient function. We show that in this kinematic limit the BDS ansatz is also satisfied. Finally, we argue that only for more general kinematics - e.g. with three gluons having similar rapidities, or where the two central gluons have similar rapidities - can a disagreement with the BDS ansatz arise.

V. Del Duca; C. Duhr; E. W. N. Glover

2008-09-10T23:59:59.000Z

248

Qualification of the Joints for the ITER Central Solenoid  

SciTech Connect

The ITER Central Solenoid has 36 interpancake joints, 12 bus joints, and 12 feeder joints in the magnet. The joints are required to have resistance below 4 nOhm at 45 kA at 4.5 K. The US ITER Project Office developed two different types of interpancake joints with some variations in details in order to find a better design, qualify the joints, and establish a fabrication process. We built and tested four samples of the sintered joints and two samples with butt-bonded joints (a total of eight joints). Both designs met the specifications. Results of the joint development, test results, and selection of the baseline design are presented and discussed in the paper. The ITER Central Solenoid (CS) consists of six modules. Each module is composed of six wound hexapancakes and one quadrapancake. The multipancakes are connected electrically and hydraulically by in-line interpancake joints. The joints are located at the outside diameter (OD) of the module. Cable in conduit conductor (CICC) high-current joints are critical elements in the CICC magnets. In addition to low resistivity, the CS joints must fit a space envelope equivalent to the regular conductor cross section and must have low hydraulic impedance and enough structural strength to withstand the hoop and compressive forces during operation, including cycling. This paper is the continuation of the work reported on the intermodule joints.

Martovetsky, N; Berryhill, A; Kenney, S

2011-09-01T23:59:59.000Z

249

Soft Error Vulnerability of Iterative Linear Algebra Methods  

Science Conference Proceedings (OSTI)

Devices become increasingly vulnerable to soft errors as their feature sizes shrink. Previously, soft errors primarily caused problems for space and high-atmospheric computing applications. Modern architectures now use features so small at sufficiently low voltages that soft errors are becoming significant even at terrestrial altitudes. The soft error vulnerability of iterative linear algebra methods, which many scientific applications use, is a critical aspect of the overall application vulnerability. These methods are often considered invulnerable to many soft errors because they converge from an imprecise solution to a precise one. However, we show that iterative methods can be vulnerable to soft errors, with a high rate of silent data corruptions. We quantify this vulnerability, with algorithms generating up to 8.5% erroneous results when subjected to a single bit-flip. Further, we show that detecting soft errors in an iterative method depends on its detailed convergence properties and requires more complex mechanisms than simply checking the residual. Finally, we explore inexpensive techniques to tolerate soft errors in these methods.

Bronevetsky, G; de Supinski, B

2007-12-15T23:59:59.000Z

250

Reformulation of nonlinear integral magnetostatic equations for rapid iterative convergence  

SciTech Connect

The integral equations of magnetostatics, conventionally given in terms of the field variables M and H, are reformulated with M and B. Stability criteria and convergence rates of the eigenvectors of the linear iteration matrices are evaluated. The relaxation factor ..beta.. in the MH approach varies inversely with permeability ..mu.., and nonlinear problems with high permeability converge slowly. In contrast, MB iteration is stable for ..beta.. < 2, and nonlinear problems converge rapidly, at a rate essentially independent of ..mu... For a permeability of 10/sup 3/, the number of iterations is reduced by two orders of magnitude over the conventional method, and at higher permeabilities the reduction is proportionally greater. The dependence of MB convergence rate on ..beta.., degree of saturation, element aspect ratio, and problem size is found numerically. An analytical result for the MB convergence rate for small nonlinear problems is found to be accurate for ..beta..less than or equal to1.2. The results are generally valid for two- and three-dimensional integral methods and are independent of the particular discretization procedures used to compute the field matrix.

Bloomberg, D.S.; Castelli, V.

1985-03-01T23:59:59.000Z

251

Position Paper11Position papers aim to synthesise some key aspect of the knowledge platform for environmental modelling and software issues. The review process is twofold - a normal external review process followed by extensive review by EMS Board members. See the Editorial in this issue.: Ten iterative steps in development and evaluation of environmental models  

Science Conference Proceedings (OSTI)

Models are increasingly being relied upon to inform and support natural resource management. They are incorporating an ever broader range of disciplines and now often confront people without strong quantitative or model-building backgrounds. These trends ... Keywords: Integrated assessment, Model testing, Sensitivity, System identification, Uncertainty, Verification

A. J. Jakeman; R. A. Letcher; J. P. Norton

2006-05-01T23:59:59.000Z

252

U.S.Statements on International Fusion Reactor (ITER) Siting Decision |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

U.S.Statements on International Fusion Reactor (ITER) Siting U.S.Statements on International Fusion Reactor (ITER) Siting Decision U.S.Statements on International Fusion Reactor (ITER) Siting Decision June 28, 2005 - 1:45pm Addthis WASHINGTON, DC - Today in Moscow, Russia, the ministers representing the six ITER parties, including Dr. Raymond L. Orbach, Director of the U.S. Department of Energy's Office of Science, announced the ITER international fusion reactor will be located at the EU site in Cadarache, France. Below are statements by U.S. government officials following the signing of the agreement at the Ministerial Meeting. The text of the announcement by the six parties is available at www.iter.org/index_newsroom.htm. Statement by U.S. Secretary of Energy Samuel W. Bodman: "Plentiful, reliable energy is critical to continued worldwide economic

253

Time parallelization of advanced operation scenario simulations of ITER plasma  

Science Conference Proceedings (OSTI)

This work demonstrates that simulations of advanced burning plasma operation scenarios can be successfully parallelized in time using the parareal algorithm. CORSICA - an advanced operation scenario code for tokamak plasmas is used as a test case. This is a unique application since the parareal algorithm has so far been applied to relatively much simpler systems except for the case of turbulence. In the present application, a computational gain of an order of magnitude has been achieved which is extremely promising. A successful implementation of the Parareal algorithm to codes like CORSICA ushers in the possibility of time efficient simulations of ITER plasmas.

Samaddar, D. [ITER Organization, Saint Paul Lez Durance, France; Casper, T. A. [Lawrence Livermore National Laboratory (LLNL); Kim, S. H. [ITER Organization, Saint Paul Lez Durance, France; Berry, Lee A [ORNL; Elwasif, Wael R [ORNL; Batchelor, Donald B [ORNL; Houlberg, Wayne A [ORNL

2013-01-01T23:59:59.000Z

254

An iterative, dynamically stabilized method of data unfolding  

E-Print Network (OSTI)

We propose a new iterative unfolding method for experimental data, making use of a regularization function. The use of this function allows one to build an improved normalization procedure for Monte Carlo spectra, unbiased by the presence of possible new structures in data. We are able to unfold, in a dynamically stable way, data spectra which can be strongly affected by fluctuations in the background subtraction and simultaneously reconstruct structures which were not initially simulated. This method also allows one to control the amount of correlations introduced between the bins of the unfolded spectrum, when the transfers of events correcting the systematic detector effects are performed.

Bogdan Malaescu

2009-07-22T23:59:59.000Z

255

Volkov solution for two laser beams and ITER  

E-Print Network (OSTI)

We find the solution of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an alectron. The practical meaning of the two laser beams is, that two laser beams impinging on a targed which is constituted from material in the form of a foam, can replace 100-200 laser beams impinging on a normal targed. It means that the nuclear fusion with two laser beams is realistic in combination with the nuclear reactor such as ITER.

Miroslav Pardy

2005-07-12T23:59:59.000Z

256

Analysis of the ITER LFS Reflectometer Transmission Line System  

Science Conference Proceedings (OSTI)

A critical issue in the design of the ITER Low Field Side (LFS) reflectometer is the transmission line (TL) system. A TL connects each launcher to a diagnostic instrument. Each TL will typically consist of ~42 m of corrugated waveguide and up to 10 miter bends. Important issues for the performance of the TL system are mode conversion and reflections. Minimizing mode conversion and reflections in the waveguide are critical to minimizing standing waves and phase errors in the reflectometer-measured phase. The performance of the corrugated waveguide and miter bends is analyzed and recommendations given.

Hanson, Gregory R [ORNL; Wilgen, John B [ORNL; Bigelow, Tim S [ORNL; Diem, Stephanie J [ORNL; Biewer, Theodore M [ORNL

2010-01-01T23:59:59.000Z

257

Volkov solution for two laser beams and ITER  

E-Print Network (OSTI)

We find the solution of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an alectron. The practical meaning of the two laser beams is, that two laser beams impinging on a targed which is constituted from material in the form of a foam, can replace 100-200 laser beams impinging on a normal targed. It means that the nuclear fusion with two laser beams is realistic in combination with the nuclear reactor such as ITER.

Pardy, M

2006-01-01T23:59:59.000Z

258

Implementing the Gaia Astrometric Global Iterative Solution (AGIS) in Java  

E-Print Network (OSTI)

This paper provides a description of the Java software framework which has been constructed to run the Astrometric Global Iterative Solution for the Gaia mission. This is the mathematical framework to provide the rigid reference frame for Gaia observations from the Gaia data itself. This process makes Gaia a self calibrated, and input catalogue independent, mission. The framework is highly distributed typically running on a cluster of machines with a database back end. All code is written in the Java language. We describe the overall architecture and some of the details of the implementation.

O'Mullane, William; Lindegren, Lennart; Hernandez, Jose; Hobbs, David

2011-01-01T23:59:59.000Z

259

Object Delineation in Noisy Images by a Modified Policy-Iteration Method  

Science Conference Proceedings (OSTI)

The contours of isolated objects in noisy images may be detected with a minimal cost contour detection algorithm. An algorithm that is based on the policy-iteration method for locating the closed minimal cost path is introduced. Computational results ... Keywords: closed minimal cost path, cost coefficient matrix, iterative methods, noisy images, object delineation, optimisation, pattern recognition, picture processing, policy-iteration method, scintigraphic images

Adrie C. M. Dumay; Mariëlle N. A. J. Claessens; Cees Roos; Jan J. Gerbrands; Johan H. C. Reiber

1992-09-01T23:59:59.000Z

260

A high-recycle divertor for ITER (International Thermonuclear Experimental Reactor)  

SciTech Connect

A coupled one-dimensional (axial/radial) edge-plasma model (SOLAR) has been used to investigate tradeoffs between collector-plate and edge-plasma conditions in a doublenull, open, high-recycle divertor (HRD) for a preliminary International Thermonuclear Experimental Reactor (ITER) design. A steady-state HRD produces in attractive high-density edge plasma (5 /times/ 10/sup 19/m/sup /minus/3/) with sufficiently low plasma temperature (10-20eV) at a tungsten plat that the sheath-accelerated ions are below sputtering threshold energies. Manageable plate heat fluxes (3-6 MW/m/sup 2/) are achieved by positioning the plate poloidal cross section at a minimum angle of 15-30/degree/ with respect to flux surfaces. 6 refs., 9 figs.

Werley, K.A.; Bathke, C.G.

1988-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Cryogenic Conduction Cooling Test of Removable Panel Mock-Up for ITER Cryostat Thermal Shield  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

K. Nam et al.

262

FILM COOLING CALCULATIONS WITH AN ITERATIVE CONJUGATE HEAT TRANSFER APPROACH USING EMPIRICAL HEAT TRANSFER COEFFICIENT CORRECTIONS.  

E-Print Network (OSTI)

??An iterative conjugate heat transfer technique was developed and automated to predict the temperatures on film cooled surfaces such as flat plates and turbine blades.… (more)

Dhiman, Sushant

2010-01-01T23:59:59.000Z

263

Status of Design and R&D for ITER Blanket in Korea  

Science Conference Proceedings (OSTI)

ITER / Proceedings of the Twentieth Topical Meeting on the Technology of Fusion Energy (TOFE-2012) (Part 1), Nashville, Tennessee, August 27-31, 2012

Duck-Hoi Kim et al.

264

Iterated and irreducible pion-photon exchange in nuclei  

E-Print Network (OSTI)

We calculate the contribution to the nuclear energy density functional which arises from iterated pion-photon exchange between nucleons. In heavy nuclei, this novel charge symmetry breaking interaction leads to an additional binding of each proton by about 0.2 MeV. Compared to that the analogous effect from irreducible pion-photon exchange is negligibly small. As a possible mechanism to resolve the Nolen-Schiffer anomaly we propose the iteration of one-photon exchange with an attractive short-range NN-interaction. The corresponding energy per proton reads: $\\bar E[\\rho_p]=(2\\alpha/15\\pi^2)(\\pi^2 -3+6 \\ln2) {\\cal A}_{pp} k_p^2$ with $\\rho_p =k_p^3/ 3\\pi^2$ the proton density and ${\\cal A}_{pp}\\approx 2 $fm an effective (in-medium) scattering length. Hints for such a value of ${\\cal A}_{pp}$ come from phenomenological Skyrme forces and from the neutron matter equation of state.

N. Kaiser

2003-12-16T23:59:59.000Z

265

Testability of AND-EXOR Based Iterative Logic Arrays  

E-Print Network (OSTI)

Iterative Logic Arrays (ILAs) are ideal as VLSI sub-systems because of their regular structure and its close resemblance with FPGAs (Field Programmable Gate Arrays). AND-EXOR based circuits are of interest in the design of very low power circuits where energy loss implied by high frequency switching is of much consideration. This paper examines the testability of AND-EXOR based Iterative Logic Arrays (ILAs). For certain ILAs it is possible to find a test set whose size remains constant irrespective of the size of the ILA, while for others it varies with array size. Former type of ILAs is known as Constant-Testable (C-Testable). It has been shown that AND-EXOR based Logic Arrays are C-Testable and size of test set is equal to number of entries in cell truth table. The test generation problem has been shown to be related to certain properties of cycles in a set of graphs derived from cell truth table. By careful analysis of these cycles an efficient test generation technique that can be easily converted to an A...

Chakraborty, Avik

2008-01-01T23:59:59.000Z

266

Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible/infrared wide angle viewing system optical design  

SciTech Connect

ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible/infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed.

Joanny, M.; Salasca, S.; Dapena, M.; Cantone, B.; Travere, J. M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Thellier, C.; Ferme, J. J. [THALES SESO, 13593 Aix-en-Provence Cedex 3 (France); Marot, L. [Department of Physics, University of Basel, 4056 Basel (Switzerland); Buravand, O. [Institut d'Optique Graduate School, 91127 Palaiseau (France); Perrollaz, G. [AMETRA, 13770 Venelles (France); Zeile, C. [INR, KIT, D-76344 Eggenstein-Leopoldshafen (Germany)

2012-10-15T23:59:59.000Z

267

A Slowly Varying Model of the Quasi-biennial Oscillation Involving Effects of Transcience, Self-acceleration and Saturation of Equatorial Waves  

Science Conference Proceedings (OSTI)

A numerical simulation of the quasi-biennial oscillations (QBO) is presented using a sophisticated one-dimensional model operating under a slowly varying WKB assumption. The roles of wave transience, wave self-acceleration and wave saturation are ...

Hiroshi Tanaka; Nobuyuki Yoshizawa

1987-05-01T23:59:59.000Z

268

Proposal of an Arc Detection Technique Based on RF Measurements for the ITER ICRF Antenna  

SciTech Connect

RF arc detection is a key operational and safety issue for the ICRF system on ITER. Indeed the high voltages inside the antenna put it at risk of arcing, which could cause substantial damage. This paper describes the various possibilities explored by circuit simulation and the strategy now considered to protect the ITER ICRF antenna from RF arcs.

Huygen, S.; Dumortier, P.; Durodie, F.; Messiaen, A.; Vervier, M.; Vrancken, M. [LPP/ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Wooldridge, E. [EURATOM/CCFE Fusion Association, Culham Science Centre (United Kingdom)

2011-12-23T23:59:59.000Z

269

Iterative Solutions for Low Lying Excited States of a Class of Schroedinger Equation  

E-Print Network (OSTI)

The convergent iterative procedure for solving the groundstate Schroedinger equation is extended to derive the excitation energy and the wave function of the low-lying excited states. The method is applied to the one-dimensional quartic potential problem. The results show that the iterative solution converges rapidly when the coupling $g$ is not too small.

R. Friedberg; T. D. Lee; W. Q. Zhao

2006-07-12T23:59:59.000Z

270

Iterative Solution for Generalized Sombrero-shaped Potential in $N$-dimensional Space  

E-Print Network (OSTI)

An explicit convergent iterative solution for the lowest energy state of the Schroedinger equation with generalized $N$-dimensional Sombrero-shaped potential is presented. The condition for the convergence of the iteration procedure and the dependence of the shape of the groundstate wave function on the parameters are discussed.

W. Q. Zhao

2007-12-25T23:59:59.000Z

271

FPA 30 year Anniversary Meeting, Washington, 2 December 2009 Slide 1 Status of ITER  

E-Print Network (OSTI)

Principal Deputy Director General of the ITER Organization #12;FPA 30 year Anniversary Meeting, Washington Operation Present HQ Building To Aix #12;FPA 30 year Anniversary Meeting, Washington, 2 December 2009 Slide Organization ~440 people by end 2009 · Another 450-500 people in the DAs working on ITER · IO and DA's started

272

Attachment to Joint Declaration of the Ministerial Meeting for ITER Moscow, 28th  

E-Print Network (OSTI)

Attachment to Joint Declaration of the Ministerial Meeting for ITER Moscow, 28th June 2005 Joint will be decided jointly, based upon the wishes of the non-Host as long as this serves the goal of promoting 5 May 2005 #12;Attachment to Joint Declaration of the Ministerial Meeting for ITER Moscow, 28th June

273

A three-dimensional adaptive method based on the iterative grid redistribution  

E-Print Network (OSTI)

such as fluid dynamics, combustion and heat transfer and others, the required density of grid pointsA three-dimensional adaptive method based on the iterative grid redistribution Desheng Wang on iterative grid redistribution technique introduced in [J. Comput. Phys. 159 (2000) 246]. The key step

Wang, Xiao-Ping

274

Performance Parameters and Development Status of ECH Transmission Line Components Suitable for ITER (A24394)  

E-Print Network (OSTI)

IAEA Technical Committee Meeting On Electron Cyclotron Resonance Heating Physics And Technology For ITER, Kloster Seeon, Germany, 2003, To Be Published In The ProceedingsIAEA Technical Committee Meeting on Electron Cyclotron Resonance Heating Physics and Technology for ITER Kloster Seeon, DE, 2003999610360

Olstad, R.A.

2003-07-14T23:59:59.000Z

275

Considerations of Selection of ECH System Transmission Line Waveguide Diameter for ITER (A25121)  

E-Print Network (OSTI)

Proc. 3rd Tech. Mtg On Electron Cyclotron Resonanxe Heating Physics And Technology For ITER, Como, Italy, 2005; General Atomics Report GA-A25121 (2005)3rd Technical Meeting on Electron Cyclotron Resonance Heating Physics and Technology for ITER Como, IT, 2005999610860

Olstad, R.A.

2005-07-07T23:59:59.000Z

276

Increasing the Locality of Iterative Methods and Its Application to the Simulation of Semiconductor Devices  

Science Conference Proceedings (OSTI)

Irregular codes are present in many scientific applications, such as finite element simulations. In these simulations the solution of large sparse linear equation systems is required, which are often solved using iterative methods. The main kernel of ... Keywords: data locality, irregular codes, iterative methods, reordering techniques, semiconductor devices simulation

J.C. Pichel; D.B. Heras; J.C. Cabaleiro; A.J. García-Loureiro; F.F. Rivera

2010-05-01T23:59:59.000Z

277

A fast iterative solver for the variable coefficient diffusion equation on a disk  

Science Conference Proceedings (OSTI)

We present an efficient iterative method for solving the variable coefficient diffusion equation on a unit disk. The equation is written in polar coordinates and is discretized by the standard centered difference approximation under the grid arrangement ... Keywords: Ginzburg-Landau vortices, iterative method, polar coordinates, variable diffusion equation

Ming-Chih Lai; Yu-Hou Tseng

2005-09-01T23:59:59.000Z

278

Conceptual study on Flexible Guidance and Docking system for ITER Remote Handling  

E-Print Network (OSTI)

1 Conceptual study on Flexible Guidance and Docking system for ITER Remote Handling Transport Cask divertors and blanket modules from the Tokamak Building to the Hot Cell Building o Addressed topics for ITER Remote Handling Transport Cask o Publications from IST team: · Isabel Ribeiro, Pedro Lima, Pedro

Ribeiro,Isabel

279

Visions for Data Management and Remote Collaboration on ITER  

NLE Websites -- All DOE Office Websites (Extended Search)

Transport And Density Peaking At Low Transport And Density Peaking At Low Collisionality On Alcator C-Mod 49 th Annual Meeting of APS - DPP Orlando, 11/14/2007 M. Greenwald, J.W. Hughes, D. Mikkelsen, J. Terry, Alcator Group C. Angioni, H. Weisen M. Greenwald, et al., APS-DPP November 2007 Particle Transport and Density Profiles ● We want to be able to predict density profile - Better fusion performance with moderate density peaking - Effects on stability, divertor operation etc. ● Results from ASDEX (Angioni et al., PRL 2003), JET (H. Weisen, et al., NF 2005) show increase in density peaking at low ν* for H-mode plasmas. - Central fueling (NBI) can play an important role as well. ● Scales to ITER (with weak fueling): n e (0)/ ~ 1.4-1.5 ● In this talk, we'll also look at an additional effect: the role of safety factor

280

Characterization of Plasma Sprayed Beryllium ITER First Wall Mockups  

Science Conference Proceedings (OSTI)

ITER first wall beryllium mockups, which were fabricated by vacuum plasma spraying the beryllium armor, have survived 3000 thermal fatigue cycles at 1 MW/sq m without damage during high heat flux testing at the Plasma Materials Test Facility at Sandia National Laboratory in New Mexico. The thermal and mechanical properties of the plasma sprayed beryllium armor have been characterized. Results are reported on the chemical composition of the beryllium armor in the as-deposited condition, the through thickness and normal to the through thickness thermal conductivity and thermal expansion, the four-point bend flexure strength and edge-notch fracture toughness of the beryllium armor, the bond strength between the beryllium armor and the underlying heat sink material, and ultrasonic C-scans of the Be/heat sink interface.

Castro, Richard G.; Vaidya, Rajendra U.; Hollis, Kendall J.

1997-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Iterative Structure of the N=4 SYM Spin Chain  

E-Print Network (OSTI)

We develop algebraic methods for finding loop corrections to the N=4 SYM dilatation generator, within the noncompact psu(1,1|2) sector. This sector gives a 't Hooft coupling lambda-dependent representation of psu(1,1|2) times psu(1|1)^2. At first working independently of the representation, we present an all-order algebraic ansatz for the lambda-dependence of this Lie algebra's generators. The ansatz solves the symmetry constraints if an auxiliary generator, h, satisfies certain simple commutation relations with the Lie algebra generators. Applying this to the psu(1,1|2) sector leads to an iterative solution for the planar three-loop dilatation generator in terms of leading order symmetry generators and h, which passes a thorough set of spectral tests. We argue also that this algebraic ansatz may be applicable to the nonplanar theory as well.

Benjamin I. Zwiebel

2008-06-11T23:59:59.000Z

282

Iterative methods for overlap and twisted mass fermions  

E-Print Network (OSTI)

We present a comparison of a number of iterative solvers of linear systems of equations for obtaining the fermion propagator in lattice QCD. In particular, we consider chirally invariant overlap and chirally improved Wilson (maximally) twisted mass fermions. The comparison of both formulations of lattice QCD is performed at four fixed values of the pion mass between 230MeV and 720MeV. For overlap fermions we address adaptive precision and low mode preconditioning while for twisted mass fermions we discuss even/odd preconditioning. Taking the best available algorithms in each case we find that calculations with the overlap operator are by a factor of 30-120 more expensive than with the twisted mass operator.

T. Chiarappa; K. Jansen; K. -I. Nagai; M. Papinutto; L. Scorzato; A. Shindler; C. Urbach; U. Wenger; I. Wetzorke

2006-09-13T23:59:59.000Z

283

Power Balance in the ITER Plasma and Divertor  

E-Print Network (OSTI)

It is planned to use atomic processes to spread out most of the heating power over the first wall and side walls to reduce the heat loads on the plasma facing components in ITER to ~ 50 MW. Calculations indicate that there will be 100 MW in bremstrahlung radiation from the plasma center, 50 MW of radiation from the plasma edge inside the separatrix and 100 MW of radiation from the scrape-off layer and divertor plasma, leaving 50 MW of power to be deposited on the divertor plates. The radiation losses are enhanced by the injection of impurities such as Neon or Argon at acceptably low levels (~0.1 % Argon, etc.) 1.

unknown authors

1995-01-01T23:59:59.000Z

284

Status of ITER neutral beam cell remote handling system  

E-Print Network (OSTI)

The ITER neutral beam cell will contain up to three heating neutral beams and one diagnostic neutral beam, and four upper ports. Though manual maintenance work is envisaged within the cell, when containment is breached, or the radiological protection is removed the maintenance must be conducted remotely. This maintenance constitutes the removal and replacement of line replaceable units, and their transport to and from a cask docked to the cell. A design of the remote handling system has been prepared to concept level which this paper describes including the development of a beam line transporter, beam source remote handling equipment, upper port remote handling equipment and equipment for the maintenance of the neutral shield. This equipment has been developed complete the planned maintenance tasks for the components of the neutral beam cell and to have inherent flexibility to enable as yet unforeseen tasks and recovery operations to be performed.

Sykes, N; Choi, C-H; Crofts, O; Crowe, R; Damiani, C; Delavalle, S; Meredith, L; Mindham, T; Raimbach, J; Tesini, A; Van Uffelen, M

2013-01-01T23:59:59.000Z

285

Safety Analysis of the US Dual Coolant Liquid Lead-Lithium ITER Test Blanket Module  

DOE Green Energy (OSTI)

The US is proposing a prototype of a dual coolant liquid lead-lithium (DCLL) DEMO blanket concept for testing in the International Thermonuclear Experimental Reactor (ITER) as an ITER Test Blanket Module (TBM). Because safety considerations are an integral part of the design process to ensure that this TBM does not adversely impact the safety of ITER, a safety assessment has been conducted for this TBM and its ancillary systems as requested by the ITER project. Four events were selected by the ITER International Team (IT) to address specific reactor safety concerns, such as VV pressurization, confinement building pressure build-up, TBM decay heat removal capability, tritium and activation products release from the TBM system, and hydrogen and heat production from chemical reactions. This paper summarizes the results of this safety assessment conducted with the MELCOR computer code.

Merrill, Brad; Reyes, Susana; Sawan, Mohamed; Wong, Clement

2006-07-01T23:59:59.000Z

286

Development of the bus joint for the ITER Central Solenoid  

SciTech Connect

The terminations of the Central Solenoid (CS) modules are connected to the bus extensions by joints located outside the CS in the gap between the CS and Torodial Field (TF) assemblies. These joints have very strict space limitations. Low resistance is a common requirement for all ITER joints. In addition, the CS bus joints will experience and must be designed to withstand significant variation in the magnetic field of several tenths of a Tesla per second during initiation of plasma. The joint resistance is specified to be less than 4 nOhm. The joints also have to be soldered in the field and designed with the possibility to be installed and dismantled in order to allow cold testing in the cold test facility. We have developed coaxial joints that meet these requirements and have demonstrated the feasibility to fabricate and assemble them in the vertical configuration. We introduced a coupling cylinder with superconducting strands soldered to the surface of the cable that can be installed in the ITER assembly hall and at the Cold Test Facility. This cylinder serves as a transition area between the CS module and the bus extension. We made two racetrack samples and tested four bus joints in our Joint Test Apparatus. Resistance of the bus joints was measured by a decay method and by a microvoltmeter; the value of the current was measured by the Hall probes. This measurement method was verified in the previous tests. The resistance of the joints varied insignificantly from 1.5 to 2 nOhm. One of the challenges associated with a soldered joint is the inability to use corrosive chemicals that are difficult to clean. This paper describes our development work on cable preparation, chrome removal, compaction, soldering, and final assembly and presents the test results.

Martovetsky, Nicolai N [ORNL] [ORNL; Irick, David Kim [ORNL] [ORNL; Kenney, Steven J [ORNL] [ORNL

2013-01-01T23:59:59.000Z

287

ITER's Tokamak Cooling Water System and the Use of ASME Codes to Comply with French Regulations for Nuclear Pressure Equipment  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Jeanette Berry; Juan Ferrada; Seokho Kim; Warren Curd; Giovanni Dell'Orco; Vladimir Barabash

288

Monotone Domain Decomposition Iterative Method and its Convergence for a Nonlinear Integro-Differential Equation of Volterra Type  

E-Print Network (OSTI)

We apply the monotone domain decomposition iterative method to a nonlinear integro-differential equation of Volterra type and prove its convergence. To do this, by adding a term in both sides of the original equation we make a linear equation to get a monotone domain decomposition iterative scheme and prove the existence, uniqueness and convergence of iterative solutions.

Myong-Gil Rim; Dong-Hyok Kim

2013-04-02T23:59:59.000Z

289

Chinese Statement on Joint Declaration in ITER MM -2 in Moscow XU Guanhua, Minister of Science and Technology  

E-Print Network (OSTI)

Chinese Statement on Joint Declaration in ITER MM - 2 in Moscow XU Guanhua, Minister of Science step towards the Joint Implementation of ITER, after several long-term and tough bilateral discussions Negotiation with other parties so as to prepare for an efficient start of joint implementation of ITER after

290

An analysis of iterated local search for job-shop scheduling.  

Science Conference Proceedings (OSTI)

Iterated local search, or ILS, is among the most straightforward meta-heuristics for local search. ILS employs both small-step and large-step move operators. Search proceeds via iterative modifications to a single solution, in distinct alternating phases. In the first phase, local neighborhood search (typically greedy descent) is used in conjunction with the small-step operator to transform solutions into local optima. In the second phase, the large-step operator is applied to generate perturbations to the local optima obtained in the first phase. Ideally, when local neighborhood search is applied to the resulting solution, search will terminate at a different local optimum, i.e., the large-step perturbations should be sufficiently large to enable escape from the attractor basins of local optima. ILS has proven capable of delivering excellent performance on numerous N P-Hard optimization problems. [LMS03]. However, despite its implicity, very little is known about why ILS can be so effective, and under what conditions. The goal of this paper is to advance the state-of-the-art in the analysis of meta-heuristics, by providing answers to this research question. They focus on characterizing both the relationship between the structure of the underlying search space and ILS performance, and the dynamic behavior of ILS. The analysis proceeds in the context of the job-shop scheduling problem (JSP) [Tai94]. They begin by demonstrating that the attractor basins of local optima in the JSP are surprisingly weak, and can be escaped with high probaiblity by accepting a short random sequence of less-fit neighbors. this result is used to develop a new ILS algorithms for the JSP, I-JAR, whose performance is competitive with tabu search on difficult benchmark instances. They conclude by developing a very accurate behavioral model of I-JAR, which yields significant insights into the dynamics of search. The analysis is based on a set of 100 random 10 x 10 problem instances, in addition to some widely used benchmark instances. Both I-JAR and the tabu search algorithm they consider are based on the N1 move operator introduced by van Laarhoven et al. [vLAL92]. The N1 operator induces a connected search space, such that it is always possible to move from an arbitrary solution to an optimal solution; this property is integral to the development of a behavioral model of I-JAR. However, much of the analysis generalizes to other move operators, including that of Nowicki and Smutnick [NS96]. Finally the models are based on the distance between two solutions, which they take as the well-known disjunctive graph distance [MBK99].

Whitley, L. Darrell (Colorado State University, Fort Collins, CO); Howe, Adele E. (Colorado State University, Fort Collins, CO); Watson, Jean-Paul (Colorado State University, Fort Collins, CO)

2003-08-01T23:59:59.000Z

291

Research Article Short Communication: Is Ethanol-Based Hand Sanitizer Involved in Acute Pancreatitis after Excessive Disinfection?—An Evaluation with the Use of PBPK Model  

E-Print Network (OSTI)

Copyright © 2012 Céline Huynh-Delerme et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. An occupational physician reported to the French Health Products Safety Agency (Afssaps) a case of adverse effect of acute pancreatitis (AP) in a teaching nurse, after multiple demonstrations with ethanol-based hand sanitizers (EBHSs) used in a classroom with defective mechanical ventilation. It was suggested by the occupational physician that the exposure to ethanol may have produced a significant blood ethanol concentration and subsequently the AP. In order to verify if the confinement situation due to defective mechanical ventilation could increase the systemic exposure to ethanol via inhalation route, a physiologically based pharmacokinetic (PBPK) modeling was used to predict ethanol blood levels. Under the worst case scenario, the simulation by PBPK modeling showed that the maximum blood ethanol concentration which can be predicted of 5.9 mg/l is of the same order of magnitude to endogenous ethanol concentration (mean = 1.1 mg/L; median = 0.4 mg/L; range = 0–35 mg/L) in nondrinker

Céline Huynh-delerme; Catherine Artigou; Laurent Bodin; Robert Tardif; Ginette Charest-tardif; Cécile Verdier; Nessryne Sater; Mostafa Ould-elhkim; Catherine Desmares

2012-01-01T23:59:59.000Z

292

Formation and Sustainment of ITPs in ITER with the Baseline Heating Mix  

SciTech Connect

Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved con nement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current pro les and negative shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. It is shown that, with a trade-o of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating con guration.

Francesca M. Poli and Charles Kessel

2012-12-03T23:59:59.000Z

293

Sixth-order and Seventh-order Iterative Methods for Solving Nonlinear Equations  

E-Print Network (OSTI)

In this article, we discuss sixth-order and seventh-order iterative methods for nonlinear equations. Derivative-based and derivative-free, both categories are presented for said iterative methods. Especially sixth-order derivative-based and derivative-free iterative families are constructed in such a way that they circumstance a wide class of sixth-order methods which are developed in last many years. Weight functions are introduced to enhance the efficiency and parametric combination gives weight-age flexibility in between weight functions.

Fayyaz Ahmad; Domingo García-Senz

2013-02-13T23:59:59.000Z

294

Total-system performance assessment for Yucca Mountain - SNL second iteration (TSPA-1993); Volume 2  

Science Conference Proceedings (OSTI)

Sandia National Laboratories has completed the second iteration of the periodic total-system performance assessments (TSPA-93) for the Yucca Mountain Site Characterization Project (YMP). These analyses estimate the future behavior of a potential repository for high-level nuclear waste at the Yucca Mountain, Nevada, site under consideration by the Department of Energy. TSPA-93 builds upon previous efforts by emphasizing YMP concerns relating to site characterization, design, and regulatory compliance. Scenarios describing expected conditions (aqueous and gaseous transport of contaminants) and low-probability events (human-intrusion drilling and volcanic intrusion) are modeled. The hydrologic processes modeled include estimates of the perturbations to ambient conditions caused by heating of the repository resulting from radioactive decay of the waste. Hydrologic parameters and parameter probability distributions have been derived from available site data. Possible future climate changes are modeled by considering two separate groundwater infiltration conditions: {open_quotes}wet{close_quotes} with a mean flux of 10 mm/yr, and {open_quotes}dry{close_quotes} with a mean flux of 0.5 mm/yr. Two alternative waste-package designs and two alternative repository areal thermal power densities are investigated. One waste package is a thin-wall container emplaced in a vertical borehole, and the second is a container designed with corrosion-resistant and corrosion-allowance walls emplaced horizontally in the drift. Thermal power loadings of 57 kW/acre (the loading specified in the original repository conceptual design) and 114 kW/acre (a loading chosen to investigate effects of a {open_quotes}hot repository{close_quotes}) are considered. TSPA-93 incorporates significant new detailed process modeling, including two- and three-dimensional modeling of thermal effects, groundwater flow in the saturated-zone aquifers, and gas flow in the unsaturated zone.

Wilson, M.L.; Barnard, R.W.; Barr, G.E.; Dockery, H.A.; Dunn, E.; Eaton, R.R.; Martinez, M.J. [Sandia National Labs., Albuquerque, NM (United States); Gauthier, J.H.; Guerin, D.C.; Lu, N. [and others

1994-04-01T23:59:59.000Z

295

Total-system performance assessment for Yucca Mountain - SNL second iteration (TSPA-1993); Volume 1  

Science Conference Proceedings (OSTI)

Sandia National Laboratories has completed the second iteration of the periodic total-system performance assessments (TSPA-93) for the Yucca Mountain Site Characterization Project (YMP). These analyses estimate the future behavior of a potential repository for high-level nuclear waste at the Yucca Mountain, Nevada, site under consideration by the Department of Energy. TSPA-93 builds upon previous efforts by emphasizing YMP concerns relating to site characterization, design, and regulatory compliance. Scenarios describing expected conditions (aqueous and gaseous transport of contaminants) and low-probability events (human-intrusion drilling and volcanic intrusion) are modeled. The hydrologic processes modeled include estimates of the perturbations to ambient conditions caused by heating of the repository resulting from radioactive decay of the waste. Hydrologic parameters and parameter probability distributions have been derived from available site data. Possible future climate changes are modeled by considering two separate groundwater infiltration conditions: {open_quotes}wet{close_quotes} with a mean flux of 10 mm/yr, and {open_quotes}dry{close_quotes} with a mean flux of 0.5 mm/yr. Two alternative waste-package designs and two alternative repository areal thermal power densities are investigated. One waste package is a thin-wall container emplaced in a vertical borehole, and the second is a container designed with corrosion-resistant and corrosion-allowance walls emplaced horizontally in the drift. Thermal power loadings of 57 kW/acre (the loading specified in the original repository conceptual design) and 114 kW/acre (a loading chosen to investigate effects of a {open_quotes}hot repository{close_quotes}) are considered. TSPA-93 incorporates significant new detailed process modeling, including two- and three-dimensional modeling of thermal effects, groundwater flow in the saturated-zone aquifers, and gas flow in the unsaturated zone.

Wilson, M.L.; Gauthier, J.H.; Barnard, R.W.; Barr, G.E.; Dockery, H.A.; Dunn, E.; Eaton, R.R.; Guerin, D.C.; Lu, N.; Martinez, M.J. [and others] [and others

1994-04-01T23:59:59.000Z

296

Power allocation for irregularly modulated MIMO signaling with iterative frequency domain detector  

Science Conference Proceedings (OSTI)

A new power allocation method for irregularly modulated signaling in single carrier point-to-point multiple input multiple output (MIMO) systems with an iterative frequencydomain (FD) soft cancellation (SC) minimum mean squared error (MMSE) equalization ...

Juha Karjalainen; Antti Tölli; Marian Codreanu; Markku Juntti; Tad Matsumoto

2009-11-01T23:59:59.000Z

297

US ITER is a strong contributor in plan to enhance international...  

NLE Websites -- All DOE Office Websites (Extended Search)

By Lynne Degitz, US ITER March 28, 2013 Tweet Widget Facebook Like Google Plus One PPPL's Russell Feder, left, and David Johnson developed key features for a modular approach to...

298

PPPL and ITER: Lab teams support the world's largest fusion experiment...  

NLE Websites -- All DOE Office Websites (Extended Search)

ITER: Lab teams support the world's largest fusion experiment with leading-edge ideas and design By John Greenwald May 7, 2013 Tweet Widget Facebook Like Google Plus One PPPL...

299

ITER & Fusion Research Reference: MEMO/10/165 Date: 05/05/2010  

E-Print Network (OSTI)

230 million. Already in April 2010 a very important contract, the Architect Engineering contract for ITER buildings was signed between F4E and the ENGAGE consortium of European industries. The Architect

300

June 28, 2005 U.S.Statements on International Fusion Reactor (ITER)  

E-Print Network (OSTI)

to produce clean, safe, renewable, and commercially-available fusion energy by the middle of this century to the ITER talks. China, the European Union, Japan, the Russian Federation, and South Korea also

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301

Quantum Fisher Information: Variational principle and simple iterative algorithm for its efficient computation  

E-Print Network (OSTI)

We derive a new variational principle for the quantum Fisher information leading to a simple iterative alternating algorithm, the convergence of which is proved. The case of a fixed measurement, i.e. the classical Fisher information, is also discussed.

Katarzyna Macieszczak

2013-12-04T23:59:59.000Z

302

U.S. PARTICIPATION IN THE ITER TEST BLANKET MODULE (TBM) PROGRAM  

E-Print Network (OSTI)

for fusion accumulated over 40 years of CANDU reactors operation will peak at 27 kg in the year 2027 and of about $200 million dollars per kg. The CANDU tritium supply will be available for use in ITER in its

Abdou, Mohamed

303

Development and feasibility of a waste package coupled reactive transport model (AREST-CT)  

Science Conference Proceedings (OSTI)

Most models that analyze the waste package and engineered barrier system (near-field) of an underground geologic repository assume constant boundary conditions at the waste form surface and constant chemical properties of the groundwater. These models are useful for preliminary modeling, iterative modeling to estimate uncertainties, and as a source for a total systems analysis. However, the chemical behavior of the system is a very important factor in the containment and release of radionuclides, and one needs to understand the underlying processes involved. Therefore, the authors are developing a model to couple the calculation of the chemical properties with the reactive transport which can be used to assess the near-field. This report describes the models being implemented and presents some simple analyses demonstrating the feasibility of the chemical and coupled transport models.

Engel, D.W.; McGrail, B.P.; Fort, J.A.; Roberts, J.S.

1994-05-01T23:59:59.000Z

304

Qualification of the US Made Conductors for ITER TF Magnet System  

Science Conference Proceedings (OSTI)

The US Domestic Agency (USDA) is one of the six suppliers of the TF conductor for ITER. In order to qualify conductors according to ITER requirements we prepared several lengths of the CICC and short samples for testing in the SULTAN facility in CRPP, Switzerland. We also fully characterized the strands that were used in these SULTAN samples. Fabrication experience and test results are presented and discussed.

Martovetsky, Nicolai N [ORNL; Hatfield, Daniel R [ORNL; Miller, John R [ORNL; Bruzzone, P. [CRPP, Switzerland; Stepanov, B. [CRPP, Switzerland; Seber, B. [University of Geneva

2010-01-01T23:59:59.000Z

305

On Iterative Solution for Linear Complementarity Problem with an $H_{+}$-Matrix  

Science Conference Proceedings (OSTI)

The numerous applications of the linear complementarity problem (LCP) in, e.g., the solution of linear and convex quadratic programming, free boundary value problems of fluid mechanics, and moving boundary value problems of economics make ... Keywords: $H_+$-matrices, $M$-matrices, $P$-matrices, (block) modulus algorithm, LCP, iterative schemes, modified AOR method, modulus-based matrix splitting iteration methods, real positive definite matrices, scaled extrapolation, strictly diagonally dominant matrices

A. Hadjidimos; M. Lapidakis; M. Tzoumas

2012-01-01T23:59:59.000Z

306

PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER  

SciTech Connect

A271 PHYSICS AND CONTROL OF ELMING H-MODE NEGATIVE CENTRAL SHEAR ADVANCED TOKAMAK SCENARIO BASED ON EXPERIMENTAL PROFILES FOR ITER. Key DIII-D AT experimental and modeling results are applied to examine the physics and control issues for ITER to operate in a negative central shear (NCS) AT scenario. The effects of a finite edge pressure pedestal and current density are included based on the DIII-D experimental profiles. Ideal and resistive stability analyses indicate that feedback control of resistive wall modes by rotational drive or flux conserving intelligent coils is crucial for these AT configurations to operate at attractive {beta}{sub N} values in the range of 3.0-3.5. Vertical stability and halo current analyses show that reliable disruption mitigation is essential and mitigation control using an impurity gas can significantly reduce the local mechanical stress to an acceptable level. Core transport and turbulence analyses demonstrate that control of the rotational shear profile is essential to maintain the good confinement necessary for high {beta}. Consideration of edge stability and core transport suggests that a sufficiently wide pedestal is necessary for the projected fusion performance. Heat flux analyses indicate that with core-only radiation enhancement the outboard peak divertor heat load is near the design limit of 10 MW/m{sup 2}

LAO,LL; CHAN,VS; EVANS,TE; HUMPHREYS,DA; LEUER,JA; MAHDAVI,MA; PETRIE,TW; SNYDER,PB; STJOHN,HE; STAEBLER,GM; STAMBAUGH,RD; TAYLOR,TS; TURNBULL,AD; WEST,WP; BRENNAN,DP

2002-11-01T23:59:59.000Z

307

Neutron imaging with coded sources: new challenges and the implementation of a simultaneous iterative reconstruction technique  

Science Conference Proceedings (OSTI)

The limitations in neutron flux and resolution (L/D) of current neutron imaging systems can be addressed with a Coded Source Imaging system with magnification (xCSI). More precisely, the multiple sources in an xCSI system can exceed the flux of a single pinhole system for several orders of magnitude, while maintaining a higher L/D with the small sources. Moreover, designing for an xCSI system reduces noise from neutron scattering, because the object is placed away from the detector to achieve magnification. However, xCSI systems are adversely affected by correlated noise such as non-uniform illumination of the neutron source, incorrect sampling of the coded radiograph, misalignment of the coded masks, mask transparency, and the imperfection of the system Point Spread Function (PSF). We argue that a model-based reconstruction algorithm can overcome these problems and describe the implementation of a Simultaneous Iterative Reconstruction Technique algorithm for coded sources. Design pitfalls that preclude a satisfactory reconstruction are documented.

Santos-Villalobos, Hector J [ORNL; Bingham, Philip R [ORNL; Gregor, Jens [University of Tennessee, Knoxville (UTK)

2013-01-01T23:59:59.000Z

308

An iterative method for extreme optics of two-level systems  

E-Print Network (OSTI)

We formulate the problem of a two-level system in a linearly polarized laser field in terms of a nonlinear Riccati-type differential equation and solve the equation analytically in time intervals much shorter than half the optical period. The analytical solutions for subsequent intervals are then stuck together in an iterative procedure to cover the scale time of the laser pulse. This approach is applicable to pulses of arbitrary (nonrelativistic) strengths, shapes and durations, thus covering the whole region of light-matter couplings from weak through moderate to strong ones. The method allows quick insight into different problems from the field of light--matter interaction. Very good quality of the method is shown by recovering with it a number of subtle effects met in earlier numerically calculated photon-emission spectra from model molecular ions, double quantum wells, atoms and semiconductors. The method presented is an efficient mathematical tool to describe novel effects in the region of, e.g., extreme nonlinear optics, i.e., when two--level systems are exposed to pulses of only a few cycles in duration and strength ensuring the Rabi frequency to approach and even exceed the laser light frequence.

R. Parzynski; M. Sobczak; A. Plucinska

2004-07-18T23:59:59.000Z

309

An Iterative Algorithm for Battery-Aware Task Scheduling on Portable Computing Platforms  

E-Print Network (OSTI)

In this work we consider battery powered portable systems which either have Field Programmable Gate Arrays (FPGA) or voltage and frequency scalable processors as their main processing element. An application is modeled in the form of a precedence task graph at a coarse level of granularity. We assume that for each task in the task graph several unique design-points are available which correspond to different hardware implementations for FPGAs and different voltage-frequency combinations for processors. It is assumed that performance and total power consumption estimates for each design-point are available for any given portable platfrom, including the peripheral components such as memory and display power usage. We present an iterative heuristic algorithm which finds a sequence of tasks along with an appropriate design-point for each task, such that a deadline is met and the amount of battery energy used is as small as possible. A detailed illustrative example along with a case study of a real-world applicati...

Khan, Jawad

2011-01-01T23:59:59.000Z

310

A Hierarchy of Nonlinear Filtered Models—Numerical Solutions  

Science Conference Proceedings (OSTI)

Five filtered models, including two that are intermediate between the balanced and the primitive equations, are studied using actual weather data. The iterative method of solution works well in most cases. The two more general models are solved ...

Trond Iversen; Thor Erik Nordeng

1984-10-01T23:59:59.000Z

311

Design and Analysis of the ITER Vertical Stability Coils  

SciTech Connect

The ITER vertical stability (VS) coils have been developed through the preliminary design phase by Princeton Plasma Physics Laboratory (PPPL). Final design, prototyping and construction will be carried out by the Chinese Participant Team contributing lab, Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The VS coils are a part of the in-vessel coil systems which include edge localized mode (ELM) coils as well as the VS coils. An overview of the ELM coils is provided in another paper at this conference. 15 The VS design employs four turns of stainless steel jacketed mineral insulated copper (SSMIC) conductors The mineral insulation is Magnesium Oxide (MgO). Joule and nuclear heat is removed by water flowing at 3 m/s through the hollow copper conductor. A key element in the design is that slightly elevated temperatures in the conductor and its support spine during operation impose compressive stresses that mitigate fatigue damage. Away from joints, and break-outs, conductor thermal stresses are low because of the axisymmetry of the winding (there are no corner bends as in the ELM coils).The 120 degree segment joint, and break-out or terminal regions are designed with similar but imperfect constraint compared with the ring coil portion of the VS. The support for the break-out region is made from a high strength copper alloy, CuCrZr. This is needed to conduct nuclear heat to the actively cooled conductor and to the vessel wall. The support "spine" for the ring coil portion of the VS is 316 stainless steel, held to the vessel with preloaded 718 bolts. Lorentz loads resulting from normal operating loads, disruption loads and loads from disruption currents in the support spine shared with vessel, are applied to the VS coil. The transmission of the Lorentz and thermal expansion loads from the "spine" to the vessel rails is via friction augmented with a restraining "lip" to ensure the coil frictional slip is minimal and acceptable. Stresses in the coil, joints, and break-outs are presented. These are compared with static and fatigue allowables. Design for fatigue is much less demanding than for the ELM coils. A total of 30,000 cycles is required for VS design. Loads on the vessel due to the thermal expansion of the coil and spine are significant. Efforts to reduce these by reducing the cross section of the spine have been made but the vessel still must support loads resulting from restraint of thermal expansion.

Peter H. Titus, et. al.

2012-09-06T23:59:59.000Z

312

Efficient Production Optimization Using Flow Network Models  

E-Print Network (OSTI)

Reservoir simulation is an important tool for decision making and field development management. It enables reservoir engineers to predict reservoir production performance, update an existing model to reproduce monitoring data, assess alternative field development scenarios and design robust production optimization strategies by taking into account the existing uncertainties. A big obstacle in automating model calibration and production optimization approaches is the massive computation required to predict the response of real reservoirs under proposed changes in the model inputs. To speed up reservoir response predictions without compromising accuracy, fast surrogate models have been proposed. These models are either derived by preserving the physics of the involved processes (e.g. mass balance equations) to provide reliable long-range predictions or are developed based solely on statistical relations, in which case they can only provide short-range predictions due to the absence of the physical processes that govern the long-term behavior of the reservoir. We present an alternative solution that combines the advantages of both statistics-based and physics-based methods by deriving the flow predictions in complex two-dimensional models from one-dimensional flow network models. The existing injection/production wells in the original model form the nodes or vertices of the flow network. Each pair of wells (nodes) in the flow network is connected using a one-dimensional numerical simulation model; hence, the entire reservoir is reduced to a connected network of one-dimensional simulation models where the coupling between the individual one-dimensional models is enforced at the nodes where network edges intersect. The proposed flow network model provides a useful and fast tool for characterizing inter-well connectivity, estimating drainage volume between each pair of wells, and predicting reservoir production over an extended period of time for optimization purposes. We estimate the parameters of the flow network model using a robust training approach to ensure that the flow network model reproduces the response of the original full model under a wide range of development strategies. This step helps preserve the flow network model's predictive power during the production optimization when development strategies can change at different iterations. The robust networks training and the subsequent production optimization iterations are computationally efficient as they are performed with the faster flow network model. We demonstrate the effectiveness and applicability of our proposed flow network modeling approach to rapid production optimization using two-phase waterflooding simulations in synthetic and benchmark models.

Lerlertpakdee, Pongsathorn

2012-08-01T23:59:59.000Z

313

Status of the 1 MeV Accelerator Design for ITER NBI  

SciTech Connect

The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D{sup -} at 1 MeV for 3600 sec. In order to realize the beam source, design and R and D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.

Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M. [ITER Organization, 13067 Saint-Paul-lez-Durance Cede (France); Bonicelli, T.; Masiello, A. [Fusion for Energy, C/Josep Pla 2, 08019 Barcelona (Spain); Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Sonato, P.; Toigo, V.; Zaccaria, P. [Consorzio RFX. Corso Stati Uniti 4 35127 Padova (Italy)

2011-09-26T23:59:59.000Z

314

Tobacco Industry Involvement in Colorado  

E-Print Network (OSTI)

Accessed May 25, 2004) Industry Summary. 1992 (est. ).11 May 2004) Tobacco Industry Involvement in Colorado Pageor (800) LUNG-USA. Tobacco Industry Involvement in Colorado

Landman, BA, Anne; Bialick, Peter

2004-01-01T23:59:59.000Z

315

"Progress in U.S. ITER Magnet Systems", Wayne Reiersen, Princeton  

NLE Websites -- All DOE Office Websites (Extended Search)

November 28, 2012, 4:15pm November 28, 2012, 4:15pm MBG Auditorium "Progress in U.S. ITER Magnet Systems", Wayne Reiersen, Princeton University Mr. Wayne Reiersen Princeton University U.S. ITER is responsible for providing the ITER Central Solenoid (CS), nine lengths of Toroidal Field (TF) Coil conductor, and Insert Coils for assessing CS and TF conductor performance. The status of the ongoing design and fabrication efforts will be reviewed. The interesting hurdles that had to be negotiated, the lingering problems, and the lessons learned will be discussed. (At the presenter's request, no video or presentation materials are available for this lecture.) Contact Information Coordinator(s): Carol Ann Austin caustin@pppl.gov Host(s): Phil Heitzenroeder pheitzen@pppl.gov PPPL Entrance Procedures

316

RAMI Analyses of Heating Neutral Beam and Diagnostic Neutral Beam Systems for ITER  

SciTech Connect

A RAMI (Reliability, Availability, Maintainability, Inspectability) analysis has been performed for the heating (and current drive) neutral beam (HNB) and diagnostic neutral beam (DNB) systems of the ITER device. The objective of these analyses is to implement RAMI engineering requirements for design and testing to prepare a reliability-centred plan for commissioning, operation, and maintenance of the system in the framework of technical risk control to support the overall ITER Project. These RAMI requirements will correspond to the RAMI targets for the ITER project and the compensating provisions to reach them as deduced from the necessary actions to decrease the risk level of the function failure modes. The RAMI analyses results have to match with the procurement plan of the systems.

Chang, D. H. [Korea Atomic Energy Research Institute(KAERI), Daejeon 305-353 (Korea, Republic of); Lee, S. [ITER-Korea Domestic Agency, National Fusion Research Institute(NFRI), Daejeon 305-333 (Korea, Republic of); Hemsworth, R.; Houtte, D. van; Okayama, K.; Sagot, F.; Schunke, B.; Svensson, L. [ITER Organization, 13067 St. Paul-lez-Durance Cedex (France)

2011-09-26T23:59:59.000Z

317

Tungsten spectroscopy relevant to the diagnostics development of ITER divertor plasmas  

DOE Green Energy (OSTI)

The ITER tokamak will have tungsten divertor tiles and, consequently, the divertor plasmas are expected to contain tungsten ions. The spectral emission from these ions can serve to diagnose the divertor for plasma parameters such as tungsten concentrations, densities, ion and electron temperatures, and flow velocities. The ITER divertor plasmas will likely have densities around 10{sup 14-15} cm{sup -3} and temperatures below 150 eV. These conditions are similar to the plasmas at the Sustained Spheromak Physics Experiment (SSPX) in Livermore. To simulate ITER divertor plasmas, a tungsten impurity was introduced into the SSPX spheromak by prefilling it with tungsten hexacarbonyl prior to the usual hydrogen gas injection and initiation of the plasma discharge. The possibility of using the emission from low charge state tungsten ions to diagnose tokamak divertor plasmas has been investigated using a high-resolution extreme ultraviolet spectrometer.

Clementson, J; Beiersdorfer, P; Magee, E W; McLean, H S; Wood, R D

2009-12-01T23:59:59.000Z

318

Query estimation and order-optimized iteration in very large federations  

SciTech Connect

Objectivity federated databases may contain many terabytes of data and span thousands of files. In such an environment, it is often easy for a user to pose a query that may return an iterator over millions of objects, requiring opening thousands of databases. This presentation describes several technologies developed for such settings: (1) a query estimator, which tells the user how many objects satisfy the query, and how many databases will be touched, prior to opening all of those files; (2) an order-optimized iterator, which behaves like an ordinary iterator except that elements are returned in an order optimized for efficient access, presorted by the database (and container) in which they reside; (3) a parallel implementation of the order-optimized iterator, allowing any number of processes in a parallel or distributed system to iterate over disjoint subcollections of terms satisfying the query, partitioned by the database or container in which the items reside. These technologies have been developed for scientific experiments that will require handling thousands of terabytes of data annually, but they are intended to be applicable in other massive data settings as well. In such environments, significant amounts of data will reside on tertiary storage, accessible via Objectivity`s recently-announced HPSS (High Performance Storage System) interface. When deployed in large-scale physics settings later in 1998, the query estimator will further inform the user of the number of tape mounts required to satisfy the query, and provide rough time estimates for data delivery. The order-optimized iterator will be connected to a cache manager that will prefetch from tape to disk the files needed by the query (known from the query estimation step), and will decide which items to deliver to the user next according to the order in which data become available in the disk cache.

Malon, D.M.; HENP Grand Challenge Collaboration

1998-05-04T23:59:59.000Z

319

Electromagnetic Analysis of ITER Diagnostic Equatorial Port Plugs During Plasma Disruptions  

Science Conference Proceedings (OSTI)

ITER diagnostic port plugs perform many functionsincluding structural support of diagnostic systems under high electromagnetic loads while allowing for diagnostic access to the plasma. The design of diagnostic equatorial port plugs (EPP) are largely driven by electromagnetic loads and associate responses of EPP structure during plasma disruptions and VDEs. This paper summarizes results of transient electromagnetic analysis using Opera 3d in support of the design activities for ITER diagnostic EPP. A complete distribution of disruption loads on the Diagnostic First Walls (DFWs), Diagnostic Shield Modules (DSMs) and the EPP structure, as well as impact on the system design integration due to electrical contact among various EPP structural components are discussed.

Y. Zhai, R. Feder, A. Brooks, M. Ulrickson, C.S. Pitcher and G.D. Loesser

2012-08-27T23:59:59.000Z

320

Progress in design and integration of the ITER Electron Cyclotron H&CD system  

Science Conference Proceedings (OSTI)

The Electron Cyclotron system for ITER is an in-kind procurement shared between five parties and the total installed power will be 24 MW, corresponding to a nominal injected power of 20 MW to the plasma, with a possible upgrade up to 48 MW (corresponding to 40 MW injected). Some critical issues have been raised and changes are proposed to simplify these procurements and to facilitate the integration into ITER. The progress in the design and the integration of the EC system into the whole project is presented in this paper, as well as some issues still under studies and some recommendations made by external expert committees.

Darbos, Caroline [ITER Joint Work Site, Cadarache; Henderson, Mark [ITER Joint Work Site, Cadarache; Kobayashi, N. [ITER Joint Work Site, Cadarache; Albajar, F. [Fusion for Energy (F4E), Barcelona, Spain; Bonicelli, T. [Fusion for Energy (F4E), Barcelona, Spain; Saibene, G. [Fusion for Energy (F4E), Barcelona, Spain; Bigelow, Timothy S [ORNL; Rasmussen, David A [ORNL; Chavan, R. [EPFL, Lausanne, Switzerland; Fasel, D. [EPFL, Lausanne, Switzerland; Hogge, J. P. [EPFL, Lausanne, Switzerland; Denisov, G. G. [Russian Academy of Science, Novgorod, Russia; Heidinger, R. [Institut fur Materialforschung II, Karlsruhe, Germany; Piosczyk, B. [Institut fur Materialforschung II, Karlsruhe, Germany; Thumm, M. [Institut fur Materialforschung II, Karlsruhe, Germany; Rao, S. L. [Institute for Plasma Research, Gandhinagar, India; Sakamoto, K. [Japan Atomic Energy Agency (JAEA), Naka; Takahaski, K. [Japan Atomic Energy Agency (JAEA), Naka; Thumm, M. [Universituet Karlsruhe, Germany

2009-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

An iterated search for influence from the future on the Large Hadron Collider  

E-Print Network (OSTI)

We analyse an iterated version of Nielsen and Ninomiya (N&N)'s proposed card game experiment to search for a specific type of backward causation on the running of the Large Hadron Collider (LHC) at CERN. We distinguish "endogenous" and "exogenous" potential causes of failure of LHC and we discover a curious "cross-talk" between their respective probabilities and occurrence timescales when N&N-style backward causation is in effect. Finally, we note a kind of "statistical cosmic censorship" preventing the influence from the future from showing up in a statistical analysis of the iterated runs.

Iain Stewart

2007-12-05T23:59:59.000Z

322

Point-Based Value Iteration for Continuous POMDPs  

Science Conference Proceedings (OSTI)

We propose a novel approach to optimize Partially Observable Markov Decisions Processes (POMDPs) defined on continuous spaces. To date, most algorithms for model-based POMDPs are restricted to discrete states, actions, and observations, but many real-world ...

Josep M. Porta; Nikos Vlassis; Matthijs T.J. Spaan; Pascal Poupart

2006-12-01T23:59:59.000Z

323

The Use of DIII-D as a Testbed for ITER ECH Transmission Line Comonents (A25064)  

E-Print Network (OSTI)

Proc. Of 3rd Tech. Mtg On Electron Cyclotron Resonance Heating Physics And Technology For ITER, Como, Italy, 2005, To Be Published In Proceedings3rd Technical Meeting on Electron Cyclotron Resonance Heating Physics and Technology for ITER Como, IT, 2005999610680

Callis, R.W.

2005-06-10T23:59:59.000Z

324

Physics and engineering results obtained with the ion cyclotron range of frequencies ITER-like antenna on JET  

SciTech Connect

This paper summarizes the operational experience of the ion cyclotron resonant frequency (ICRF) ITER-like antenna on JET aiming at substantially increasing the power density in the range of the requirements for ITER combined with load resiliency. An in-depth description of its commissioning, operational aspects and achieved performances is presented.

Durodie, F. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Nightingale, M. [EURATOM / UKAEA, Abingdon, UK; Mayoral, M. -L. [EURATOM / UKAEA, Abingdon, UK; Ongena, J. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Argouarch, A. [CEA Cadarache, St. Paul lex Durance, France; Berger-By, G. [CEA Cadarache, St. Paul lex Durance, France; Goulding, Richard Howell [ORNL

2012-01-01T23:59:59.000Z

325

Short Survey: Intelligent switching expert system for delayed coking unit based on iterative learning strategy  

Science Conference Proceedings (OSTI)

Delayed coking is the most effective process to decarbonize and demetallize heavy petroleum residues. However, it relies much on the field engineers' experiences and expertise in practice for operating the controllers effectively and compatibly in delayed ... Keywords: Delayed coking, Expert system, Intelligent control, Iterative learning

Xiaodong Yu; Yujie Wei; Dexian Huang; Yongheng Jiang; Bo Liu; Yihui Jin

2011-07-01T23:59:59.000Z

326

Double iterative optimisation for metabolic network-based drug target identification  

Science Conference Proceedings (OSTI)

The goal of drug discovery is to find molecules that manipulate enzymes in order to increase or decrease the production of desired compounds while incurring minimum side-effects. An important part of this problem is the identification of the target ... Keywords: E coli, bioinformatics, data mining, drug discovery, drug target identification, iterative optimisation, metabolic networks, target enzymes

Bin Song; Padmavati Sridhar; Tamer Kahveci; Sanjay Ranka

2009-05-01T23:59:59.000Z

327

Thirty states sign ITER nuclear fusion plant deal 1 hour, 28 minutes ago  

E-Print Network (OSTI)

than 30 countries signed a deal on Tuesday to build the world's most advanced nuclear fusion reactor nuclear reactors, but critics argue it could be at least 50 years before a commercially viable reactorThirty states sign ITER nuclear fusion plant deal 1 hour, 28 minutes ago Representatives of more

328

Exploiting phase inter-dependencies for faster iterative compiler optimization phase order searches  

Science Conference Proceedings (OSTI)

The problem of finding the most effective set and ordering of optimization phases to generate the best quality code is a fundamental issue in compiler optimization research. Unfortunately, the exorbitantly large phase order search spaces in current compilers ... Keywords: iterative compilation, optimization ordering, search space pruning

Michael R. Jantz; Prasad A. Kulkarni

2013-09-01T23:59:59.000Z

329

Iterative approach to the characteristic time for chemical reactions of type A + B ! C + D  

E-Print Network (OSTI)

The analytic solution for the kinetic description of binary reactions can be seen as the continuum version of a basic discrete iterate mapping. This fact allows a clear definition of the reaction characteristic time which takes the backward effect into account.

R. Aldrovandi

2013-10-13T23:59:59.000Z

330

Requirements for US regulatory approval of the International Thermonuclear Experimental Reactor (ITER)  

SciTech Connect

The International Thermonuclear Experimental Reactor (ITER) is the first fusion machine that will have sufficient decay heat and activation product inventory to pose potential nuclear safety concerns. As a result, nuclear safety and environmental issues will be much more important in the approval process for the design, siting, construction, and operation of ITER in the United States than previous fusion devices, such as the Tokamak Fusion Test Reactor. The purpose of this report is (a) to provide an overview of the regulatory approval process for a Department of Energy (DOE) nuclear facility; (b) to present the dose limits used by DOE to protect workers, the public, and the environment from the risks of exposure to radiation and hazardous materials; (c) to discuss some key nuclear safety-related issues that must be addressed early in the Engineering Design Activities (EDA) to obtain regulatory approval; and (d) to provide general guidelines to the ITER Joint Central Team (JCT) concerning the development of a regulatory framework for the ITER project.

Petti, D.A.; Haire, J.C.

1993-12-01T23:59:59.000Z

331

An iterative solution to the four-peg Tower of Hanoi problem  

Science Conference Proceedings (OSTI)

One of the variations of the Towers of Hanoi puzzle allows for p pegs, and for four pegs the solution to this variation is shown to have a simple structure which can be used to derive an iterative solution to the problem.

Appie van de Liefvoort

1990-01-01T23:59:59.000Z

332

Annual Report of the EURATOM/CCFE Fusion Programme 2010/11 8 ITER Systems  

E-Print Network (OSTI)

to the ITER heating, diagnostic and remote handling systems in particular. Fusion for Energy (F4E) content, the ion temperature and flow; · Remote handling system, in particular the design for the Neutral Remote Handling requirements; · Full manufacturing / assembly assessments. Figure 8.5: Development

333

Annual Report of the EURATOM/CCFE Fusion Programme 2011/12 8 ITER Systems  

E-Print Network (OSTI)

and Remote Handling etc.) in Europe; 8ITERSystems · Seek to play other design roles in R&D of ITER specialist the helium (ash) content, the ion temperature and flow; · Remote handling system, in particular the design Dump and Calorimeter designs. 8.2.3 REMOTE HANDLING CCFE was awarded a grant to complete the conceptual

334

ITER Engineering Design Activities -R & DITER-In-Vessel Remote Handling  

E-Print Network (OSTI)

ITER Engineering Design Activities - R & DITER- In-Vessel Remote Handling Blanket Module Remote Handling Project (L-6) Divertor Remote Handling Project (L-7) Objective To develop and demonstrate handling equipment, port handling equipment, auxiliary remote handling tools and a blanket mockup structure

335

TF Ripple Loss of Alpha Particles from the ITER Interim Design: Simulation and Theory  

E-Print Network (OSTI)

and potentially severe localized wall damage in fusion reactors. In this paper we show guiding center code (GC, substantial ad hoc normalization factors were required. This is understandable, since the loss criterion used 12, 1995, ITER JCT, San Diego, CA (private com- munication, S. Putvinski). 2: R. B. White, et al

336

THE STRUCTURE OF TWO-PARABOLIC SPACE: PARABOLIC DUST AND ITERATION.  

E-Print Network (OSTI)

THE STRUCTURE OF TWO-PARABOLIC SPACE: PARABOLIC DUST AND ITERATION. JANE GILMAN Abstract. A non-elementary M¨obius group generated by two- parabolics is determined up to conjugation by one complex para] to obtain an additional struc- ture for the parameter space, which we term the two-parabolic space

Gilman, Jane

337

Iterative methods for neutron transport eigenvalue Fynn Scheben and Ivan G. Graham  

E-Print Network (OSTI)

. Numer. Anal., 26 (1989), pp. 66­87. [3] G. I. Bell and S. Glasstone, Nuclear Reactor Theory, Reinhold iterative methods for computing criticality in nuclear reactors. In general this requires the solution and optimal performance of existing nuclear reactors is an important task of great environmental significance

Graham, Ivan

338

Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach? Part 2  

Science Conference Proceedings (OSTI)

The recent work 'Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach?' speculated that the second eigenfunction could be built using essentially the same 'building brick' approach that obtained the first eigenfunction in LA-UR-12-21928. This note shows that the speculation was at least partially correct, but not complete.

Booth, Thomas E. [Los Alamos National Laboratory

2012-07-11T23:59:59.000Z

339

The Iterative Unitary Matrix Multiply Method and Its Application to Quantum Kicked Rotator  

E-Print Network (OSTI)

We use the iterative unitary matrix multiply method to calculate the long time behavior of the resonant quantum kicked rotator with a large denominator. The delocalization time is exponentially large. The quantum wave delocalizes through degenerate states. At last we construct a nonresonant quantum kicked rotator with delocalization.

Tao Ma

2007-09-14T23:59:59.000Z

340

ccsd-00002019,version1-18Oct2004 Stabilization of Burn Conditions in an ITER FEAT  

E-Print Network (OSTI)

,i 92.8 MW ; (6) these limits contain the required values for steady state operation for the range reactions together with an external RF electron and ion heating, with a small contribution of joule heating will constitute the operating point for the ITER-FEAT like tokamak reactor used in this work.[5,6] Here, we

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

The Linear Stability Properties of Medium- to High- n TAEs in ITER  

SciTech Connect

This document provides a detailed report on the successful completion of the DOE OFES Theory Milestone for FY2007: Improve the simulation resolution of linear stability properties of Toroidal Alfvén Eigenmodes (TAE) driven by energetic particles and neutral beams in ITER by increasing the numbers of toroidal modes used to 15.

Gorelenkov, N N; Budny, R V; Kessel, C E; Kramer, G J; McCune, D; Manickam, J; Nazikian, R

2008-02-14T23:59:59.000Z

342

An efficient preconditioned iterative solution of fully-coupled elastohydrodynamic lubrication problems  

Science Conference Proceedings (OSTI)

This paper presents the fast preconditioned iterative solution to large sparse linear systems arising from the application of Newton and quasi-Newton methods to fully coupled elastohydrodynamic lubrication line and point contact problems. The new blockwise ... Keywords: Elastohydrodynamic lubrication, Finite element method, Fully coupled approach, Linear elasticity, Multigrid, Preconditioned GMRES

Sarfraz Ahmed; Christopher E. Goodyer; Peter K. Jimack

2012-05-01T23:59:59.000Z

343

Fusion Engineering and Design 81 (2006) 393405 Breeding Blanket Modules testing in ITER  

E-Print Network (OSTI)

to be assessed. TBM replacement occurs in the ITER hot cell, where the whole TBMs/shield plug system is remotely HCCB TBM). 6. Remote handling, maintenance, and safety considerations The general assumed rule. A view of a possible port cell volume occupation is shown in Fig. 14. Either the addition of a hot cell

Abdou, Mohamed

344

Fusion Engineering and Design 46 (1999) 207220 ITER divertor, design issues and research and development  

E-Print Network (OSTI)

of the PFCs is performed ex-vessel in a hot cell, where it is anticipated the refurbishment of 60 cassettes, November 1997. [19] E. Martin, et al., Design of the ITER Divertor Remote Handling System; 19th SOFT, tritium inventory, impurity control, armour lifetime, electromagnetic loads, diagnostics, and remote

Raffray, A. René

345

A Preliminary Analysis of Dose Rates Associated with ITER CVCS Equipment/Area Location  

DOE Green Energy (OSTI)

A preliminary analysis of the ITER Chemical and Volume Control System (CVCS) Area was performed to assess dose rates outside the walls and ceiling of the facility after 1.5 years of operation at shutdown, 2 days, and 10 days after shutdown. For this purpose a simplified Monte Carlo computer model was developed using the MCNP (MCNP5 Ver. 1.51) code. Two components are included: the smaller filter tank and the larger ion exchanger. These pieces of equipment are associated with the Integrated Blanket ELM Divertor Primary Heat Transfer System, which will have the largest dose rates associated with activated corrosion products during operation in comparison with other systems. The ion exchanger contained two source regions, a 1.2-m-thick resin bed above a 0.55 m-thick skirt, and a 0.8-m-thick water region. The filter constituted an additional source. Thus the model consisted of three sources (filter, resin, water), homogeneously distributed within the appropriate source regions. However, much of the results (that address individual isotopes) are presented with the two sources in the ion exchanger combined. In these cases the sources are referred to as the 'ion exchanger source' and the 'filter source.' Dimensions for the facility and components, as well as source isotopes and strengths, and material densities, were supplied by US ITER. Because of its simplification, the model does not contain pipes. Consequently, radiation streaming through pipe penetrations, radiation emanating from the pipes, and shielding from the pipes were not considered in this analysis. Dose rates on the outside of two walls and the ceiling were calculated. The two walls are labeled as the 'long' wall (aligned with the X-axis) and the 'short' wall (aligned with the Y-axis). These walls and ceiling were nominally set to 30-cm-thick concrete. In the original analysis, standard concrete (2.3 g/cc density) was used. In addition to the shielding walls/ceiling, a floor and an additional wall opposite the long wall were added for photon scattering contributions. These were both 10-cm-thick, standard concrete structures. Other components (tanks, pipes, etc.), that were not included in the model, would potentially add additional scattering and shielding. Possibly these additional effects will be addressed in a later, more detailed analysis. The room was 29.6 m in length (X-axis), but was limited to 15 m in the model. The inside width (Y axis) and height (Z axis) were 4 m and 3.4 m, respectively. The origin for the model was located inside the room at the corner opposite the long wall and adjacent to the short wall at the floor level. The room was filled with air at standard temperature and pressure. The stainless steel (SS304) wall thicknesses for the ion exchanger and filter were 2.2 cm and 0.8 cm, respectively. The axial center of the filter was located 140 cm from the short wall and 100 cm from the long wall (outer surface). The axial center of the ion exchanger was located 440 cm from the short wall and 250 cm from the long wall (inner surface). The resin was assumed to be a homogeneous mixture of equal atom density fractions of hydrogen and carbon* at a specified density of 1.136 g/cc. The filter material was assumed to be homogeneous carbon at a specified density of 1.8 g/cc. If the filter media were stainless steel and the accumulated activity were the same, the dose rate outside the filter would be lower, provided the density of the stainless steel sintered filter material is significantly higher than 1.8g/cc. The densities of the water and air were assumed to be 1.0 g/cc and 1.096E-3 g/cc, respectively. The model included 10 small volumes placed outside the model adjacent to the wall at locations where the dose rates were expected to be highest and which showed to a degree the fall-off of the dose rate with distance along a particular wall or ceiling. These 'tally cells' are shown in Fig. 2 and are described in Table 1. Each cell had dimensions of 50 cm x 50 cm x 1 cm and was oriented so that the 1-cm-thick dimension was perpendicular to the wall again

Blakeman, Edward D [ORNL; Ilas, Dan [ORNL; Petrov, Andrei Y [ORNL

2012-03-01T23:59:59.000Z

346

Scheduling Parallel Iterative Applications on Volatile Resources Henri Casanova  

E-Print Network (OSTI)

model where the bandwidth capacity of the master for sending application data to workers is limited grids. We develop master-worker scheduling schemes that attempt to achieve good trade-offs between, e.g., desktop grids, master bandwidth is limited and processors are temporarily reclaimed

Casanova, Henri

347

Twin-Screw Extruder Development for the ITER Pellet Injection System  

SciTech Connect

The ITER pellet injection system is comprised of devices to form and accelerate pellets, and will be connected to inner wall guide tubes for fueling, and outer wall guide tubes for ELM pacing. An extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with a gas gun into the plasma. The ITER pellet injection system is required to provide a plasma fueling rate of 120 Pa-m3/s (900 mbar-L/s) and durations of up to 3000 s. The fueling pellets will be injected at a rate up to 10 Hz and pellets used to trigger ELMs will be injected at higher rates up to 20 Hz. A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. A one-fifth ITER scale prototype has been built and has demonstrated the production of a continuous solid deuterium extrusion. The 27 mm diameter, intermeshed, counter-rotating extruder screws are rotated at a rate up to ?5 rpm. Deuterium gas is pre-cooled and liquefied and solidified in separate extruder barrels. The precooler consists of a deuterium gas filled copper coil suspended in a separate stainless steel vessel containing liquid nitrogen. The liquefier is comprised of a copper barrel connected to a Cryomech AL330 cryocooler, which has a machined helical groove surrounded by a copper jacket, through which the pre-cooled deuterium condenses. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at ?15 K) before it is forced through the extruder die. The die forms the extrusion to a 3 mm x 4 mm rectangular cross section. Design improvements have been made to improve the pre-cooler and liquefier heat exchangers, to limit the loss of extrusion through gaps in the screws. This paper will describe the design improvements for the next iteration of the extruder prototype.

Meitner, Steven J [ORNL; Baylor, Larry R [ORNL; Combs, Stephen Kirk [ORNL; Fehling, Dan T [ORNL; McGill, James M [ORNL; Rasmussen, David A [ORNL; Leachman, J. W. [University of Wisconsin, Madison

2009-01-01T23:59:59.000Z

348

Non-iterative joint decoding and signal processing: universal coding approach for channels with memory  

E-Print Network (OSTI)

A non-iterative receiver is proposed to achieve near capacity performance on intersymbol interference (ISI) channels. There are two main ingredients in the proposed design. i) The use of a novel BCJR-DFE equalizer which produces optimal soft estimates of the inputs to the ISI channel given all the observations from the channel and L past symbols exactly, where L is the memory of the ISI channel. ii) The use of an encoder structure that ensures that L past symbols can be used in the DFE in an error free manner through the use of a capacity achieving code for a memoryless channel. Computational complexity of the proposed receiver structure is less than that of one iteration of the turbo receiver. We also provide the proof showing that the proposed receiver achieves the i.i.d. capacity of any constrained input ISI channel. This DFE-based receiver has several advantages over an iterative (turbo) receiver, such as low complexity, the fact that codes that are optimized for memoryless channels can be used with channels with memory, and finally that the channel does not need to be known at the transmitter. The proposed coding scheme is universal in the sense that a single code of rate r; optimized for a memoryless channel, provides small error probability uniformly across all AWGN-ISI channels of i.i.d. capacity less than r: This general principle of a proposed non-iterative receiver also applies to other signal processing functions, such as timing recovery, pattern-dependent noise whiten ing, joint demodulation and decoding etc. This makes the proposed encoder and receiver structure a viable alternative to iterative signal processing. The results show significant complexity reduction and performance gain for the case of timing recovery and patter-dependent noise whitening for magnetic recording channels.

Nangare, Nitin Ashok

2003-05-01T23:59:59.000Z

349

Small Mock-Up Fabrication and High Heat Flux Test for Preparing the 2nd Qualification of the ITER Blanket First Wall  

Science Conference Proceedings (OSTI)

ITER Systems / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 1)

Dong Won Lee; Suk Kwon Kim; Young-Dug Bae; Yang Il Jung; Jeong Yong Park; Yong Hwan Jeong; Byung Yoon Kim

350

An iterative procedure to obtain inverse response functions for thick-target correction of measured charged-particle spectra  

E-Print Network (OSTI)

A new method for correcting charged-particle spectra for thick target effects is described. Starting with a trial function, inverse response functions are found by an iterative procedure. The variances corresponding to the measured spectrum are treated similiarly and in parallel. Oscillations of the solution are avoided by rebinning the data to finer bins during a correction iteration and back to the original or wider binning after each iteration. This thick-target correction method has been used for data obtained with the MEDLEY facility at the The Svedberg Laboratory, Uppsala, Sweden, and is here presented in detail and demonstrated for two test cases.

S. Pomp; U. Tippawan

2006-08-25T23:59:59.000Z

351

An Axial Dispersion Model for Gas - Liquid Reactors Based on the Penetration Theory  

E-Print Network (OSTI)

An axial dispersion reactor model for gas -- liquid reaction systems is proposed in this paper based on the penetration theory. The mass transfer mechanism accompanied by a chemical irreversible first-order reaction is mathematically treated in a new way in order to use its results to develop the model conveniently. Analytical solutions can be obtained for the equation system involving linear differential equations by using of the eigenvalues of the equation system. In addition, an iteration procedure is given to solve the nonlinear differential equation system numerically. The influences of the important model parameters on the concentration profile, the mass transfer and the reactant conversion are also studied. 1997 Elsevier Science S.A.

Jinfu Wang; Shejiao Han; Fei Wei; Zhiqing Yu; Yong Jin

1997-01-01T23:59:59.000Z

352

Hybrid preconditioning for iterative diagonalization of ill-conditioned generalized eigenvalue problems in electronic structure calculations  

E-Print Network (OSTI)

The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for {\\em ab initio} electronic structure calculations. We propose a hybrid preconditioning scheme to effectively combine global and locally accelerated preconditioners for rapid iterative diagonalization of such eigenvalue problems. In partition-of-unity finite-element (PUFE) pseudopotential density-functional calculations, employing a nonorthogonal basis, we show that the hybrid preconditioned block steepest descent method is a cost-effective eigensolver, outperforming current state-of-the-art global preconditioning schemes, and comparably efficient for the ill-conditioned generalized eigenvalue problems produced by PUFE as the locally optimal block preconditioned conjugate-gradient method for the well-conditioned standard eigenvalue problems produced by planewave methods.

Cai, Yunfeng; Pask, John E; Sukumar, N

2013-01-01T23:59:59.000Z

353

Assessment of database for interaction of tritium with ITER plasma facing materials  

SciTech Connect

The present work surveys recent literature on hydrogen isotope interactions with Be, SS and Inconels, Cu, C, and V, and alloys of Cu and V. The goals are (1) to provide input to the International Thermonuclear Experimental Reactor (ITER) team to help with tritium source term estimates for the Early Safety and Environmental Characterization Study and (2) to provide guidance for planning additional research that will be needed to fill gaps in the present materials database. Properties of diffusivity, solubility, permeability, chemical reactions, Soret effect, recombination coefficient, surface effects, trapping, porosity, layered structures, interfaces, and oxides are considered. Various materials data are tabulated, and a matrix display shows an assessment of the quality of the data available for each main property of each material. Recommendations are made for interim values of diffusivity and solubility to be used, pending further discussion by the ITER community.

Dolan, T.J.; Anderl, R.A.

1994-09-01T23:59:59.000Z

354

Design and Overview of 100 kV Bushing for the DNB Injector of ITER  

Science Conference Proceedings (OSTI)

The 100 kV bushing is one of the most important and technologically challenging Safety Important Class (SIC) components of the Diagnostic Neutral Beam (DNB) injector of ITER. It forms interface between gas insulated electrical transmission line and torus primary vacuum and acts as a vacuum feedthrough of ITER. Design optimization has been carried out to meet the electric and structural requirements based on its classification. Unlike HNB bushing, single stage bushing is designed to provide 100 kV isolation. Finite Element Analysis (FEA) based optimization has been carried out for electrostatic and structural analysis. Manufacturing assembly sequence is studied and presented in this paper. However validation of the same is foreseen from manufacturer.

Shah, Sejal; Bandyopadhyay, M.; Rotti, C.; Singh, M. J.; Roopesh, G.; Chakraborty, A. K. [ITER-India, Institute for Plasma Research, Gandhinagar-382025, Gujarat (India); Rajesh, S. [ITER-India, Institute for Plasma Research, Gandhinagar-382025, Gujarat (India); Microelectronics and Materials Physics Labs, P.O.Box 4500, FIN-90014 University of Oulu (Finland); Nishad, S.; Srusti, B. [DesignTech Systems Ltd, Banjara Hills, Hyderabad, Andhra Pradesh-500034 (India); Schunke, B.; Hemsworth, R.; Chareyre, J.; Svensson, L. [ITER Organisation, Route de Vinon, CS 90 046, 13067 St. Paul lez Durance Cedex (France)

2011-09-26T23:59:59.000Z

355

Review of the International Thermonuclear Experimental Reactor (ITER) detailed design report  

SciTech Connect

Dr. Martha Krebs, Director, Office of Energy Research at the US Department of Energy (DOE), wrote to the Fusion Energy Sciences Advisory Committee (FESAC), in letters dated September 23 and November 6, 1996, requesting that FESAC review the International Thermonuclear Experimental Reactor (ITER) Detailed Design Report (DDR) and provide its view of the adequacy of the DDR as part of the basis for the United States decision to enter negotiations with the other interested Parties regarding the terms and conditions for an agreement for the construction, operations, exploitation and decommissioning of ITER. The letter from Dr. Krebs, referred to as the Charge Letter, provided context for the review and a set of questions of specific interest.

1997-04-18T23:59:59.000Z

356

In-Vessel Coil Material Failure Rate Estimates for ITER Design Use  

SciTech Connect

The ITER international project design teams are working to produce an engineering design for construction of this large tokamak fusion experiment. One of the design issues is ensuring proper control of the fusion plasma. In-vessel magnet coils may be needed for plasma control, especially the control of edge localized modes (ELMs) and plasma vertical stabilization (VS). These coils will be lifetime components that reside inside the ITER vacuum vessel behind the blanket modules. As such, their reliability is an important design issue since access will be time consuming if any type of repair were necessary. The following chapters give the research results and estimates of failure rates for the coil conductor and jacket materials to be used for the in-vessel coils. Copper and CuCrZr conductors, and stainless steel and Inconel jackets are examined.

L. C. Cadwallader

2013-01-01T23:59:59.000Z

357

Arbitrary accuracy iterative phase estimation algorithm as a two qubit benchmark  

E-Print Network (OSTI)

We discuss the implementation of an iterative quantum phase estimation algorithm, with a single ancillary qubit. We suggest using this algorithm as a benchmark for multi-qubit implementations. Furthermore we describe in detail the smallest possible realization, using only two qubits, and exemplify with a superconducting circuit. We discuss the robustness of the algorithm in the presence of gate errors, and show that 7 bits of precision is obtainable, even with very limited gate accuracies.

M. Dobsicek; G. Johansson; V. S. Shumeiko; G. Wendin

2006-10-25T23:59:59.000Z

358

Global convergence of diluted iterations in maximum-likelihood quantum tomography  

E-Print Network (OSTI)

In this paper we present an inexact stepsize selection for the Diluted R\\rho R algorithm, used to obtain the maximum likelihood estimate to the density matrix in quantum state tomography. We give a new interpretation for the diluted R\\rho R iterations that allows us to prove the global convergence under weaker assumptions. Thus, we propose a new algorithm which is globally convergent and suitable for practical implementation.

D. S. Gonçalves; M. A. Gomes-Ruggiero; C. Lavor

2013-06-13T23:59:59.000Z

359

Development of a YAG laser system for the edge Thomson scattering system in ITER  

SciTech Connect

A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).

Hatae, T.; Yatsuka, E.; Hayashi, T.; Ono, T.; Kusama, Y. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Ibaraki 311-0193 (Japan); Yoshida, H. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)

2012-10-15T23:59:59.000Z

360

A spatial multigrid iterative method for two-dimensional discrete-ordinates transport problems  

E-Print Network (OSTI)

Iterative solutions of the Boltzmann transport equation are computationally intensive. Spatial multigrid methods have led to efficient iterative algorithms for solving a variety of partial differential equations; thus, it is natural to explore their application to transport equations. Manteuffel et al. conducted such an exploration in one spatial dimension, using two-cell inversions as the relaxation or smoothing operation, and reported excellent results. In this dissertation we extensively test Manteuffel??s one-dimensional method and our modified versions thereof. We demonstrate that the performance of such spatial multigrid methods can degrade significantly given strong heterogeneities. We also extend Manteuffel??s basic approach to two-dimensional problems, employing four-cell inversions for the relaxation operation. We find that for uniform homogeneous problems the two-dimensional multigrid method is not as rapidly convergent as the one-dimensional method. For strongly heterogeneous problems the performance of the two-dimensional method is much like that of the one-dimensional method, which means it can be slow to converge. We conclude that this approach to spatial multigrid produces a method that converges rapidly for many problems but not for others. That is, this spatial multigrid method is not unconditionally rapidly convergent. However, our analysis of the distribution of eigenvalues of the iteration operators indicates that this spatial multigrid method may work very well as a preconditioner within a Krylov iteration algorithm, because its eigenvalues tend to be relatively well clustered. Further exploration of this promising result appears to be a fruitful area of further research.

Lansrud, Brian David

2005-05-01T23:59:59.000Z

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361

Control of non-controllable quantum systems: A quantum control algorithm based on Grover iteration  

E-Print Network (OSTI)

A new notion of controllability, eigenstate controllability, is defined for finite-dimensional bilinear quantum mechanical systems which are neither strongly completely controllably nor completely controllable. And a quantum control algorithm based on Grover iteration is designed to perform a quantum control task of steering a system, which is eigenstate controllable but may not be (strongly) completely controllable, from an arbitrary state to a target state.

Chen-Bin Zhang; Dao-Yi Dong; Zong-Hai Chen

2005-03-02T23:59:59.000Z

362

Absolutely and uniformly convergent iterative approach to inverse scattering with an infinite radius of convergence  

DOE Patents (OSTI)

A method and system for solving the inverse acoustic scattering problem using an iterative approach with consideration of half-off-shell transition matrix elements (near-field) information, where the Volterra inverse series correctly predicts the first two moments of the interaction, while the Fredholm inverse series is correct only for the first moment and that the Volterra approach provides a method for exactly obtaining interactions which can be written as a sum of delta functions.

Kouri, Donald J. (Houston, TX); Vijay, Amrendra (Houston, TX); Zhang, Haiyan (Houston, TX); Zhang, Jingfeng (Houston, TX); Hoffman, David K. (Ames, IA)

2007-05-01T23:59:59.000Z

363

Lessons learnt from ITER safety & licensing for DEMO and future nuclear fusion facilities  

E-Print Network (OSTI)

One of the strong motivations for pursuing the development of fusion energy is its potentially low environmental impact and very good safety performance. But this safety and environmental potential can only be fully realized by careful design choices. For DEMO and other fusion facilities that will require nuclear licensing, S&E objectives and criteria should be set at an early stage and taken into account when choosing basic design options and throughout the design process. Studies in recent decades of the safety of fusion power plant concepts give a useful basis on which to build the S&E approach and to assess the impact of design choices. The experience of licensing ITER is of particular value, even though there are some important differences between ITER and DEMO. The ITER project has developed a safety case, produced a preliminary safety report and had it examined by the French nuclear safety authorities, leading to the licence to construct the facility. The key technical issues that arose during ...

Taylor, Neill

2013-01-01T23:59:59.000Z

364

High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system  

Science Conference Proceedings (OSTI)

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20 deg. - 40 deg. from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Doane, J.; Olstad, R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Henderson, M. [ITER Organization, CS90 046, 13067 St. Paul lez Durance Cedex (France)

2011-06-15T23:59:59.000Z

365

Uncertainty assessment and analysis of ITER in-VV tritium inventory determination  

Science Conference Proceedings (OSTI)

Tracking of tritium inventories on ITER will be essential to ensure that the safety limits established for the mobilizable tritium inventory in the vacuum vessel are not violated. Tritium will be delivered to the ITER site from outside suppliers. Staring with the tritium imports the value of tritium inventory at ITER site will be known with a certain error that will propagate in time. During plasma operation, shot by shot measurements of the tritium delivered to the Torus and recovered will allow the amount of tritium trapped in the Torus to be computed at the end of the day. A case study for different measuring techniques and several measuring points for the tritium recovered from Torus have been done. An alternative method is to measure overnight the variation in the inventory of the storage and delivery system and the associated error when this method will be employed are presented. In order to reduce the errors on the tritium trapped in-vessel, at certain time intervals a method of global tritium inventory will be performed. The method envisages the transfer of all the mobilizable tritium from the plant and measurement of this inventory in the self-assay beds from the storage and delivery system. Evaluation of the most important sources of error for the tritium trapped in-vessel and means of minimization are eventually presented. (authors)

Cristescu, I. R.; Cristescu, I.; Glugla, M. [FzK, Tritium Laboratory, POBox 3640, 76021 Karlsruhe (Germany); Murdoch, D. [EFDA CSU, MPI fuer Plasmaphysik, Garching (Germany); Ciattaglia, S. [ITER IT, CEA Cadarache, 13108 St. Paul-lez-Durance (France)

2008-07-15T23:59:59.000Z

366

RMP ELM Suppression in DIII-D Plasmas with ITER Similar Shapes and Collisionalities  

SciTech Connect

Large Type-I edge localized modes (ELMs) are completely eliminated with small n = 3 resonant magnetic perturbations (RMP) in low average triangularity, = 0.26, plasmas and in ITER similar shaped (ISS) plasmas, = 0.53, with ITER relevant collisionalities ve 0.2. Significant differences in the RMP requirements and in the properties of the ELM suppressed plasmas are found when comparing the two triangularities. In ISS plasmas, the current required to suppress ELMs is approximately 25% higher than in low average triangularity plasmas. It is also found that the width of the resonant q95 window required for ELM suppression is smaller in ISS plasmas than in low average triangularity plasmas. An analysis of the positions and widths of resonant magnetic islands across the pedestal region, in the absence of resonant field screening or a self-consistent plasma response, indicates that differences in the shape of the q profile may explain the need for higher RMP coil currents during ELM suppression in ISS plasmas. Changes in the pedestal profiles are compared for each plasma shape as well as with changes in the injected neutral beam power and the RMP amplitude. Implications of these results are discussed in terms of requirements for optimal ELM control coil designs and for establishing the physics basis needed in order to scale this approach to future burning plasma devices such as ITER.

Evans, T.E. [General Atomics, San Diego; Fenstermacher, M. E. [Lawrence Livermore National Laboratory (LLNL); Moyer, R.A. [University of California, San Diego; Osborne, T. H. [General Atomics; Watkins, J. G. [Sandia National Laboratories (SNL); Gohil, P. [General Atomics; Joseph, I. [University of California, San Diego; Schaffer, M. J. [General Atomics, San Diego; Baylor, Larry R [ORNL; Becoulet, M. [CEA Cadarache, St. Paul lex Durance, France; Boedo, J.A. [University of California, San Diego; Burrell, K. H. [General Atomics; DeGrassie, J. S. [General Atomics, San Diego; Finken, K. H. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Jernigan, Thomas C [ORNL; Jakubowski, M. W. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Lehnen, M. [Forschungszentrum Julich, Julich, Germany; Leonard, A. W. [General Atomics; Lonnroth, J. [Association Euratom-Tekes, Finland; Nardon, E. [CEA Cadarache, St. Paul lex Durance, France; Parail, V. [EURATOM / UKAEA, UK; Schmitz, O. [Forschungszentrum Julich, Julich, Germany; Unterberg, B. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; West, W.P. [General Atomics, San Diego

2008-01-01T23:59:59.000Z

367

Identifying 802.11 traffic from passive measurements using iterative Bayesian inference  

E-Print Network (OSTI)

Abstract—In this paper, we propose a classification scheme that differentiates Ethernet and WLAN TCP flows based on measurements collected passively at the edge of a network. This scheme computes two quantities, the fraction of wireless TCP flows and the degree of belief that a TCP flow traverses a WLAN inside the network, using an iterative Bayesian inference algorithm that we developed. We prove that this iterative Bayesian inference algorithm converges to the unique maximum likelihood estimate (MLE) of these two quantities. Furthermore, it has the advantage that it can handle any general-classification problem given the marginal distributions of these classes. Numerical and experimental evaluations demonstrate that our classification scheme obtains accurate results. We apply this scheme to two sets of traces collected from two campus networks: one set collected from UMass in mid 2005 and the other collected from UConn in late 2010. Our technique infers that 4%–7 % and 52%–55 % of incoming TCP flows traverse an IEEE 802.11 wireless link in these two networks, respectively. Index Terms—IEEE 802.11 wireless LAN, iterative Bayesian inference, TCP ACK-pairs, wireless traffic detection.

Wei Wei; Sharad Jaiswal; Jim Kurose; Don Towsley; Kyoungwon Suh; Bing Wang

2006-01-01T23:59:59.000Z

368

Hydrogen lines in the infrared region and spectral background for the thomson scattering diagnostics of the iter divertor plasma  

Science Conference Proceedings (OSTI)

Calculations are made of the plasma spectral background, which is important for the Thomson scattering diagnostics in the ITER divertor. Theoretical grounds have been elaborated for computing the hydrogen spectral line shapes in the infrared spectral region for a divertor plasma in ITER. The shape of the P-7 Paschen line (transition n = 7 {yields} n = 3) located near the laser scattering signal has been calculated for various lines of sight in the ITER divertor. Contributions from different mechanisms of broadening the P-7 line have been examined. The spectral intensities of bremsstrahlung and photorecombination continuum have been calculated. All calculations use data on the spatial distribution of temperatures and densities of all species of plasma particles computed with the SOLPS4.3 code for basic operation regimes of the ITER divertor.

Lisitsa, V. S. [National Research Center Kurchatov Institute, Tokamak Physics Institute (Russian Federation); Mukhin, E. E. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Kadomtsev, M. B.; Kukushkin, A. B. [National Research Center Kurchatov Institute, Tokamak Physics Institute (Russian Federation); Kukushkin, A. S. [ITER Organization, Cadarache (France); Kurskiev, G. S. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Levashova, M. G. [National Research Center Kurchatov Institute, Tokamak Physics Institute (Russian Federation); Tolstyakov, S. Yu. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

2012-02-15T23:59:59.000Z

369

Report of a technical evaluation panel on the use of beryllium for ITER plasma facing material and blanket breeder material  

SciTech Connect

Beryllium because of its low atomic number and high thermal conductivity, is a candidate for both ITER first wall and divertor surfaces. This study addresses the following: why beryllium; design requirements for the ITER divertor; beryllium supply and unirradiated physical/mechanical property database; effects of irradiation on beryllium properties; tritium issues; beryllium health and safety; beryllium-coolant interactions and safety; thermal and mechanical tests; plasma erosion of beryllium; recommended beryllium grades for ITER plasma facing components; proposed manufacturing methods to produce beryllium parts for ITER; emerging beryllium materials; proposed inspection and maintenance techniques for beryllium components and coatings; time table and costs; and the importance of integrating materials and manufacturing personnel with designers.

Ulrickson, M.A. [ed.] [Sandia National Labs., Albuquerque, NM (United States); Manly, W.D. [Oak Ridge National Lab., TN (United States); Dombrowski, D.E. [Brush Wellman, Inc., Cleveland, OH (United States)] [and others

1995-08-01T23:59:59.000Z

370

On Forward-in-Time Differencing for Fluids: Stopping Criteria for Iterative Solutions of Anelastic Pressure Equations  

Science Conference Proceedings (OSTI)

In this note, the authors address the practical issue of selecting appropriate stopping criteria for iterative solutions to the elliptic pressure equation arising in nonoscillatory, forward-in-time Eulerian and semi-Lagrangian anelastic fluid ...

Piotr K. Smolarkiewicz; Vanda Grubis?i?; Len G. Margolin

1997-04-01T23:59:59.000Z

371

An $O(\\sqrt{n}\\log \\frac{(x^0)^Ts^0}{\\epsilon})$ iteration primal-dual ...  

E-Print Network (OSTI)

An $O(\\sqrt{n}\\log \\frac{(x^0)^Ts^0}{\\epsilon})$ iteration primal-dual path- following method, based on wide neighborhoods and large updates, for monotone ...

372

Modeling Tokamak Discharges During Startup in DIII-D and Predictions for ITER  

E-Print Network (OSTI)

Bull. Am. Phys. Soc. 54, 166 (2009)51st American Physical Society Annual Meeting of Division of Plasma Physics Atlanta Georgia, US, 2009999616675

Budny, R.V.

2009-08-21T23:59:59.000Z

373

Runaway Electron Confinement Modeling for DIII-D, Alcator C-Mod, and ITER (A26880)  

E-Print Network (OSTI)

Proceedings Of 23rd IAEA Fusion Energy Conference, October 11-16, 2010, Daejeon, Republic Of Korea, Http://www-pub.iaea.org/mtcd/meetings/cn180_papers.asp, Paper THS/9-223rd IAEA Fusion Energy Conference Daejeon, KP, 2010999617990

Izzo, V.A.

2010-11-12T23:59:59.000Z

374

ITER Predictions Using the GYRO Verified and Experimentally Validated TGLF Transport Model (A26874)  

E-Print Network (OSTI)

Proceedings Of 23rd IAEA Fusion Energy Conference, October 11-16, 2010, Daejeon, Republic Of Korea, Http://www-pub.iaea.org/mtcd/meetings/cn180_papers.asp, Paper THC/3-0323rd IAEA Fusion Energy Conference Daejeon, KP, 2010999617985

Kinsey, J.E.

2010-11-12T23:59:59.000Z

375

Experiment and Modeling of ITER Demonstration Discharges in the DIII-D Tokamak (A26899)  

E-Print Network (OSTI)

Proceedings Of 23rd IAEA Fusion Energy Conference, October 11-16, 2010, Daejeon, Republic Of Korea, Http://www-pub.iaea.org/mtcd/meetings/cn180_papers.asp, Paper EXC/P2-0523rd IAEA Fusion Energy Conference Daejeon, KP, 2010999618065

Park, J.M.

2010-10-13T23:59:59.000Z

376

ITER Neutronics Modeling Using Hybrid Monte Carlo/Deterministic and CAD-Based Monte Carlo Methods  

Science Conference Proceedings (OSTI)

Technical Paper / Special Issue on the 16th Biennial Topical Meeting of the Radiation Protection and Shielding Division / Radiation Transport and Protection

Ahmad M. Ibrahim; Scott W. Mosher; Thomas M. Evans; Douglas E. Peplow; Mohamed E. Sawan; Paul P. H. Wilson; John C. Wagner; Thad Heltemes

377

Development of CAD-to-MCNP Model Conversion System and Its Application to ITER  

Science Conference Proceedings (OSTI)

MC Calculations / Special Issue on the 11th International Conference on Radiation Shielding and the 15th Topical Meeting of the Radiation Protection and Shielding Division (PART 3) / Miscellaneous

Satoshi Sato; Hiromasa Iida; Kentaro Ochiai; Chikara Konno; Takeo Nishitani; Hidetsugu Morota; Hesham Nashif; Masao Yamada; Fukuzo Masuda; Shigeyuki Tamamizu; Hiroyuki Maesaka

378

A competitive iterative procedure using a time-indexed model for ...  

E-Print Network (OSTI)

Aug 19, 2013 ... in a real production cell with the objective to minimize a weighted sum of ..... the price of the higher LP bound is paid for by the much longer ...

379

Thermal modeling of W rod armor.  

Science Conference Proceedings (OSTI)

Sandia has developed and tested mockups armored with W rods over the last decade and pioneered the initial development of W rod armor for International Thermonuclear Experimental Reactor (ITER) in the 1990's. We have also developed 2D and 3D thermal and stress models of W rod-armored plasma facing components (PFCs) and test mockups and are applying the models to both short pulses, i.e. edge localized modes (ELMs), and thermal performance in steady state for applications in C-MOD, DiMES testing and ITER. This paper briefly describes the 2D and 3D models and their applications with emphasis on modeling for an ongoing test program that simulates repeated heat loads from ITER ELMs.

Nygren, Richard Einar

2004-09-01T23:59:59.000Z

380

Beam optics in a MeV-class multi-aperture multi-grid accelerator for the ITER neutral beam injector  

SciTech Connect

In a multi-aperture multi-grid accelerator of the ITER neutral beam injector, the beamlets are deflected due to space charge repulsion between beamlets and beam groups, and also due to magnetic field. Moreover, the beamlet deflection is influenced by electric field distortion generated by grid support structure. Such complicated beamlet deflections and the compensations have been examined utilizing a three-dimensional beam analysis. The space charge repulsion and the influence by the grid support structure were studied in a 1/4 model of the accelerator including 320 beamlets. Beamlet deflection due to the magnetic field was studied by a single beamlet model. As the results, compensation methods of the beamlet deflection were designed, so as to utilize a metal bar (so-called field shaping plate) of 1 mm thick beneath the electron suppression grid (ESG), and an aperture offset of 1 mm in the ESG.

Kashiwagi, M.; Taniguchi, M.; Umeda, N.; Tobari, H.; Watanabe, K.; Inoue, T. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, 311-0193 Japan (Japan); Esch, H. P. L. de [CEA Cadarache, 13067 St. Paul Lez Durance Cedex (France); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Boilson, D.; Hemsworth, R. S.; Tanaka, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2012-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Appendix V Public Involvement Plan  

NLE Websites -- All DOE Office Websites (Extended Search)

V V Public Involvement Plan Revision No.: 6 February 2008 Federal Facility Agreement and Consent Order (FFACO) FFACO, Appendix V February 2008 i FFACO Public Involvement Plan U.S. Department of Energy National Nuclear Security Administration Nevada Site Office Las Vegas, Nevada U.S. Department of Defense Defense Threat Reduction Agency Detachment 1, Nevada Operations Mercury, Nevada U.S. Department of Energy Office of Legacy Management Grand Junction, Colorado FFACO, Appendix V February 2008 ii Preface The Public Involvement Plan serves two purposes: it provides a broad public involvement strategy, and fulfills requirements contained in the Federal Facility Agreement and Consent Order (FFACO) relating to public awareness and participation. Under the FFACO, agreed to by

382

Public Involvment Plan - Rifle, Colorado  

Office of Legacy Management (LM)

4-TAR 4-TAR MAC-GWRIF 7.1 UMTRA Ground Water Project Public Involvement Plan for the Environmental Assessment of Ground Water Compliance at the New and Old Rifle, Colorado, Uranium Mill Tailings Sites May 1999 Prepared by U.S. Department of Energy Grand Junction Office Grand Junction, Colorado Work performed under DOE Contract No. DE-AC13-96GJ87335 Public Involvement Plan for the Rifle UMTRA Sites Page 2 Introduction This Public Involvement Plan is tiered to the Uranium Mill Tailings Remedial Action (UMTRA) Ground Water Project Public Participation Plan dated October 1997. This Public Involvement Plan applies to both the Old and New Rifle, Colorado, UMTRA Project sites and details the activities that have been or will be carried out to meet the public participation requirements of the

383

ITER Progress  

E-Print Network (OSTI)

With nearly 700 FED members and a strong financial balance sheet, I am pleased to report that the state of our Fusion Energy Division is strong. I would like to take this opportunity to thank our previous Chair, Professor Jake Blanchard (University of Wisconsin-Madison) for his tireless efforts on behalf of FED. This letter summarizes some of the ongoing activities at ANS, plans for the 17 th ANS Topical Meeting on the Technology of Fusion Energy (TOFE), and activities related to the Fusion Energy Science Advisory Committee (FESAC). FESAC As Chair of the ANS Fusion Energy Division, I am honored to serve as an Ex-Officio member of FESAC. During my tenure on the Committee, FESAC has so far met only once (July 19, 2005). Among the presentations given at that meeting was a report by the Facilities Panel chaired by Dr. Jill Dahlberg of NRL. The Panel was appointed following a request from Dr. Orbach in April of 2005 and charged with identifying the “unique and complimentary characteristics of each of the three major US toroidal fusion facilities ” (C-MOD, DIII-D, and NSTX), how the three facilities contribute to fusion science and the

Miley Hora; Strait Taylor

2005-01-01T23:59:59.000Z

384

Non-linear inversion modeling for Ultrasound Computer Tomography: transition from soft to hard tissues imaging  

E-Print Network (OSTI)

Non-linear inversion modeling for Ultrasound Computer Tomography: transition from soft to hard, the tomographic procedure used is adapted to broadband data acquired in scattering configurations while, Iterative Approximation, Soft Tissues Imaging, Hard Tissues Imaging, Breast, Bones 1. INTRODUCTION

385

3D automatic anatomy segmentation based on iterative graph-cut-ASM  

SciTech Connect

Purpose: This paper studies the feasibility of developing an automatic anatomy segmentation (AAS) system in clinical radiology and demonstrates its operation on clinical 3D images. Methods: The AAS system, the authors are developing consists of two main parts: object recognition and object delineation. As for recognition, a hierarchical 3D scale-based multiobject method is used for the multiobject recognition task, which incorporates intensity weighted ball-scale (b-scale) information into the active shape model (ASM). For object delineation, an iterative graph-cut-ASM (IGCASM) algorithm is proposed, which effectively combines the rich statistical shape information embodied in ASM with the globally optimal delineation capability of the GC method. The presented IGCASM algorithm is a 3D generalization of the 2D GC-ASM method that they proposed previously in Chen et al.[Proc. SPIE, 7259, 72590C1-72590C-8 (2009)]. The proposed methods are tested on two datasets comprised of images obtained from 20 patients (10 male and 10 female) of clinical abdominal CT scans, and 11 foot magnetic resonance imaging (MRI) scans. The test is for four organs (liver, left and right kidneys, and spleen) segmentation, five foot bones (calcaneus, tibia, cuboid, talus, and navicular). The recognition and delineation accuracies were evaluated separately. The recognition accuracy was evaluated in terms of translation, rotation, and scale (size) error. The delineation accuracy was evaluated in terms of true and false positive volume fractions (TPVF, FPVF). The efficiency of the delineation method was also evaluated on an Intel Pentium IV PC with a 3.4 GHZ CPU machine. Results: The recognition accuracies in terms of translation, rotation, and scale error over all organs are about 8 mm, 10 deg. and 0.03, and over all foot bones are about 3.5709 mm, 0.35 deg. and 0.025, respectively. The accuracy of delineation over all organs for all subjects as expressed in TPVF and FPVF is 93.01% and 0.22%, and all foot bones for all subjects are 93.75% and 0.28%, respectively. While the delineations for the four organs can be accomplished quite rapidly with average of 78 s, the delineations for the five foot bones can be accomplished with average of 70 s. Conclusions: The experimental results showed the feasibility and efficacy of the proposed automatic anatomy segmentation system: (a) the incorporation of shape priors into the GC framework is feasible in 3D as demonstrated previously for 2D images; (b) our results in 3D confirm the accuracy behavior observed in 2D. The hybrid strategy IGCASM seems to be more robust and accurate than ASM and GC individually; and (c) delineations within body regions and foot bones of clinical importance can be accomplished quite rapidly within 1.5 min.

Chen, Xinjian; Bagci, Ulas [Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Building 10 Room 1C515, Bethesda, Maryland 20892-1182 and Life Sciences Research Center, School of Life Sciences and Technology, Xidian University, Xi'an 710071 (China); Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Building 10 Room 1C515, Bethesda, Maryland 20892-1182 (United States)

2011-08-15T23:59:59.000Z

386

Development of the prototype pneumatic transfer system for ITER neutron activation system  

SciTech Connect

The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system.

Cheon, M. S.; Seon, C. R.; Pak, S.; Lee, H. G. [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2012-10-15T23:59:59.000Z

387

Concept development for the ITER equatorial port visible/infrared wide angle viewing system  

Science Conference Proceedings (OSTI)

The ITER equatorial port visible/infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R and D topics are outlined.

Reichle, R.; Beaumont, B.; Boilson, D.; Bouhamou, R.; Direz, M.-F.; Encheva, A.; Henderson, M.; Kazarian, F.; Lamalle, Ph.; Lisgo, S.; Mitteau, R.; Patel, K. M.; Pitcher, C. S.; Pitts, R. A.; Prakash, A.; Raffray, R.; Schunke, B.; Snipes, J.; Diaz, A. Suarez; Udintsev, V. S. [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul-lez-Durance (France); and others

2012-10-15T23:59:59.000Z

388

Alpha Heating in ITER L-mode and H-mode Plasma  

Science Conference Proceedings (OSTI)

There are many uses of predictions of ITER plasma performance. One is assessing requirements of different plasma regimes. For instance, what current drive and control are needed for steady state. The heating, current drive, and torque systems planned for initial DT operation are negative ion neutral beam injection (NB), ion cyclotron resonance (IC), and electron cyclotron resonance (EC). Which combinations of heating are optimal. What are benefits of the torques, current drive, and fueling using NB. What are the shine-through power and optimum voltage for the NB? What are optimal locations and aiming of the EC launchers? Another application is nuclear licensing (e.g. System integrity, how many neutrons).

R.V. Budny

2011-07-18T23:59:59.000Z

389

Applying Remote Handling Attributes to the ITER Neutral Beam Cell Monorail Crane  

E-Print Network (OSTI)

The maintenance requirements for the equipment in the ITER Neutral Beam Cell requires components to be lifted and transported within the cell by remote means. To meet this requirement, the provision of an overhead crane with remote handling capabilities has been initiated. The layout of the cell has driven the design to consist of a monorail crane that travels on a branched monorail track attached to the cell ceiling. This paper describes the principle design constraints and how the remote handling attributes were applied to the concept design of the monorail crane, concentrating on areas where novel design solutions have been required and on the remote recovery requirements and solutions.

Crofts, O; Raimbach, J; Tesini, A; Choi, C-H; Damiani, C; Van Uffelen, M

2013-01-01T23:59:59.000Z

390

On the iterated Crank-Nicolson for hyperbolic and parabolic equations in numerical relativity  

E-Print Network (OSTI)

The iterated Crank-Nicolson is a predictor-corrector algorithm commonly used in numerical relativity for the solution of both hyperbolic and parabolic partial differential equations. We here extend the recent work on the stability of this scheme for hyperbolic equations by investigating the properties when the average between the predicted and corrected values is made with unequal weights and when the scheme is applied to a parabolic equation. We also propose a variant of the scheme in which the coefficients in the averages are swapped between two corrections leading to systematically larger amplification factors and to a smaller numerical dispersion.

Gregor Leiler; Luciano Rezzolla

2006-01-31T23:59:59.000Z

391

An Experimental Examination of the Loss-of-Flow Accident Phenomenon for Prototypical ITER Divertor Channels of Y = 0 and Y = 2  

SciTech Connect

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pump was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.

Marshall, Theron D. [Rensselaer Polytechnic Institute (United States); McDonald, Jimmie M. [Sandia National Laboratories (United States); Cadwallader, Lee C. [Idaho National Engineering and Environmental Laboratory (United States); Steiner, Don [Rensselaer Polytechnic Institute (United States)

2000-01-15T23:59:59.000Z

392

An experimental examination of the loss-of-flow accident phenomenon for prototypical ITER divertor channels of Y=0 and Y=2  

SciTech Connect

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pump was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.

Marshall, T.D.; McDonald, J.M.; Cadwallader, L.C.; Steiner, D.

2000-01-01T23:59:59.000Z

393

Community Involvement Fund | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Community Involvement Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Community Involvement Fund Overview The success of EM's legacy waste cleanup mission depends largely on the support of informed and engaged stakeholders. Cleanup activities have the potential to affect the health of the public, the environment, and the future of the communities that either host or are located near EM sites. Therefore, it is critical that EM receive public input from local citizens and community organizations prior to making cleanup decisions. In December 2010, EM partnered with the New Mexico Community Foundation

394

Development of a Twin-Screw D-2 Extruder for the ITER Pellet Injection System  

SciTech Connect

A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. The extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with single-stage gas gun into the plasma. A one-fifth ITER scale prototype extruder has been built to produce a continuous solid deuterium extrusion. Deuterium gas is precooled and liquefied before being introduced into the extruder. The precooler consists of a copper vessel containing liquid nitrogen surrounded by a deuterium gas filled copper coil. The liquefier is comprised of a copper cylinder connected to a Cryomech AL330 cryocooler, which is surrounded by a copper coil that the precooled deuterium flows through. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at approximate to 15 K) before it is forced through the extruder nozzle. A viewport located below the extruder nozzle provides a direct view of the extrusion. A camera is used to document the extrusion quality and duration. A data acquisition system records the extruder temperatures, torque, and speed, upstream, and downstream pressures. This paper will describe the prototype twin-screw extruder and initial extrusion results.

Meitner, Steven J [ORNL; Baylor, Larry R [ORNL; Carbajo, Juan J [ORNL; Combs, Stephen Kirk [ORNL; Fehling, Dan T [ORNL; Foust, Charles R [ORNL; McFee, Marshall T [ORNL; McGill, James M [ORNL; Rasmussen, David A [ORNL; Sitterson, R G [ORNL; Sparks, Dennis O [ORNL; Qualls, A L [ORNL

2009-07-01T23:59:59.000Z

395

A protection system for the JET ITER-like wall based on imaging diagnostics  

SciTech Connect

The new JET ITER-like wall (made of beryllium and tungsten) is more fragile than the former carbon fiber composite wall and requires active protection to prevent excessive heat loads on the plasma facing components (PFC). Analog CCD cameras operating in the near infrared wavelength are used to measure surface temperature of the PFCs. Region of interest (ROI) analysis is performed in real time and the maximum temperature measured in each ROI is sent to the vessel thermal map. The protection of the ITER-like wall system started in October 2011 and has already successfully led to a safe landing of the plasma when hot spots were observed on the Be main chamber PFCs. Divertor protection is more of a challenge due to dust deposits that often generate false hot spots. In this contribution we describe the camera, data capture and real time processing systems. We discuss the calibration strategy for the temperature measurements with cross validation with thermal IR cameras and bi-color pyrometers. Most importantly, we demonstrate that a protection system based on CCD cameras can work and show examples of hot spot detections that stop the plasma pulse. The limits of such a design and the associated constraints on the operations are also presented.

Arnoux, G.; Balboa, I.; Balshaw, N.; Beldishevski, M.; Cramp, S.; Felton, R.; Goodyear, A.; Horton, A.; Kinna, D.; McCullen, P.; Obrejan, K.; Patel, K.; Lomas, P. J.; Rimini, F.; Stamp, M.; Stephen, A.; Thomas, P. D.; Williams, J.; Wilson, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); and others

2012-10-15T23:59:59.000Z

396

Stray RF Power Estimates From EC Exploitation During ITER Plasma Operations  

SciTech Connect

The EC H and CD system of ITER tokamak is an essential tool for all the phases of ITER operation. Different levels of EC power are required through all the plasma discharge: up to 6.7 MW for assisting the breakdown and burn through, up to 20 MW for current drive and saw-teeth control from the equatorial launcher and up to 20 MW for NTM stabilization from the upper launchers. The assistance to breakdown and burn through is characterized by a very low (if not negligible) RF power absorption by the plasma. A significant level of stray radiation may also arise from partial absorption due to non-optimal plasma parameters and/or wrong injected polarization. The stray power radiated in the vacuum chamber is estimated as a first step toward mitigating potential harmful consequence to in-vessel structures and diagnostics. Power loading of the chamber walls (peek power and average power density for straight beam propagation in the empty chamber) and diffuse stray radiation effects are simulated to infer suitable strategies to avoid damage to first wall and to microwave sensitive components.

Gandini, F.; Henderson, M.; Darbos, C.; Gassmann, T.; Purohit, D.; Omori, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Nazare, C. [Assystem Facilities, 78067 Saint Quentin en Yvelines Cedex (France)

2011-12-23T23:59:59.000Z

397

ITER Core Imaging X-Ray Spectrometer Conceptual Design and Performance Assessment - Phase 2  

SciTech Connect

During Phase 2 of our study of the CIXS conceptual design we have tackled additional important issues that are unique to the ITER environment. These include the thermal control of the crystal and detector enclosures located in an environment with a 100-250 C ambient temperature, tritium containment, and the range of crystal and detector movement based on the need for spectral adjustments and the desire to make measurements of colder plasmas. In addressing these issues we have selected a ''Dewar''-type enclosure for the crystals and detectors. Applying realistic view factors for radiant heat and making allowance for conduction we have made engineering studies of this enclosure and showed that the cooling requirements can be solved and the temperature can be kept sufficiently constant without compromising the specification parameters of the CIXS. We have chosen a minimum 3 mm combined thickness of the six beryllium windows needed in a Dewar-type enclosure and showed that a single window of 0.5 mm thickness satisfies tritium containment requirements. For measuring the temperature in cooler ITER plasmas, we have chosen to use the K-shell lines of Fe24+. Iron is the preferred choice because its radiation can be analyzed with the identical CIXS settings used for analyzing the tungsten radiation, i.e., essentially no adjustments besides a simple crystal rotation need to be made. We have, however, included an xy{theta}-drive motor arrangement in our design for fine adjustments and full rotation of the crystal mounts.

Beiersdorfer, P; Wen, J; Dunn, J; Morris, K

2011-01-02T23:59:59.000Z

398

A new visible spectroscopy diagnostic for the JET ITER-like wall main chamber  

Science Conference Proceedings (OSTI)

In preparation for ITER, JET has been upgraded with a new ITER-like wall (ILW), whereby the main plasma facing components, previously of carbon, have been replaced by mainly Be in the main chamber and W in the divertor. As part of the many diagnostic enhancements, a new, survey, visible spectroscopy diagnostic has been installed for the characterization of the ILW. An array of eight lines-of-sight (LOS) view radially one of the two JET neutral beam shine through areas (W coated carbon fibre composite tiles) at the inner wall. In addition, one vertical LOS views the solid W tile at the outer divertor. The light emitted from the plasma is coupled to a series of compact overview spectrometers, with overall wavelength range of 380-960 nm and to one high resolution Echelle overview spectrometer covering the wavelength range 365-720 nm. The new survey diagnostic has been absolutely calibrated in situ by means of a radiometric light source placed inside the JET vessel in front of the whole optical path and operated by remote handling. The diagnostic is operated in every JET discharge, routinely monitoring photon fluxes from intrinsic and extrinsic impurities (e.g., Be, C, W, N, and Ne), molecules (e.g., BeD, D{sub 2}, ND) and main chamber and divertor recycling (typically D{alpha}, D{beta}, and D{gamma}). The paper presents a technical description of the diagnostic and first measurements during JET discharges.

Maggi, C. F. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Brezinsek, S. [Forschungszentrum Juelich GmbH, EURATOM Association, D-52425 Juelich (Germany); Stamp, M. F.; Griph, S.; Heesterman, P.; Hogben, C.; Horton, A.; Meigs, A.; Studholme, W.; Zastrow, K.-D. [EURATOM/CCFE, Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Morlock, C. [EFDA-CSU Garching, Boltzmannstrasse 2, 85748 Garching (Germany); Collaboration: JET-EFDA Contributors

2012-10-15T23:59:59.000Z

399

Recent Advances on Hydrogenic Retention in ITER's Plasma-Facing Materials: BE, C, W.  

SciTech Connect

Management of tritium inventory remains one of the grand challenges in the development of fusion energy and the choice of plasma-facing materials is a key factor for in-vessel tritium retention. The Atomic and Molecular Data Unit of the International Atomic Energy Agency organized a Coordinated Research Project (CRP) on the overall topic of tritium inventory in fusion reactors during the period 2001-2006. This dealt with hydrogenic retention in ITER's plasma-facing materials, Be, C, W, and in compounds (mixed materials) of these elements as well as tritium removal techniques. The results of the CRP are summarized in this article together with recommendations for ITER. Basic parameters of diffusivity, solubility and trapping in Be, C and W are reviewed. For Be, the development of open porosity can account for transient hydrogenic pumping but long term retention will be dominated by codeposition. Codeposition is also the dominant retention mechanism for carbon and remains a serious concern for both Be and C containing layers. Hydrogenic trapping in unirradiated tungsten is low but will increase with ion and neutron damage. Mixed materials will be formed in a tokamak and these can also retain significant amounts of hydrogen isotopes. Oxidative and photon-based techniques for detritiation of plasma-facing components are described.

Skinner, C H; Alimov, Kh; Bekris, N; Causey, R A; Clark, R.E.H.; Coad, J P; Davis, J W; Doerner, R P; Mayer, M; Pisarev, A; Roth, J

2008-03-29T23:59:59.000Z

400

ITER Progress Highlights of the 8 th IAEA Technical Meeting on Fusion Power Plant Safety  

E-Print Network (OSTI)

First, I would like to personally thank Dr. Said Abdel-Khalik, the outgoing chair of the Fusion Energy Division (FED), for his service during his term. Said now serves not only as the past chair, but he has assumed the role of FED’s liaison to the ANS Public Policy Committee. I am pleased to report that the state of our division is quite strong. Division membership has exceeded 750 for three years in a row, and the student membership has grown to more than 200. These numbers reflect the strength and growth in the fusion community. ITER has ramped up dramatically in recent months with many team members moving from Naka and Garching to the Joint Work site in Cadarache, France. Current plans call for delivery of a new baseline design in the late spring of next year. In the U.S., NIF has demonstrated its full system performance on a single beam basis and is expected to have 25 % of the beams operational by January 2007. Truly, it is a very exciting time in the fusion community! Recently, Dr. Susana Reyes left the United States for a new position with the ITER safety team. In order to give her utmost attention to this exciting opportunity, Susana elected to

Plan U. S; Participation Iter

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario  

SciTech Connect

Experiments on Alcator C-Mod have addressed several issues for the ITER 15 MA baseline scenario from 2009-2012. Rampup studies show ICRF can save significant V-s, and that an H-mode in the ramp can be utilized to save 50% more. ICRF modifications to li(1) are minimal, although the Te profile is peaked relative to ohmic in the plasma center, and alter sawtooth onset times. Rampdown studies show H-modes can be routinely sustained, avoiding an OH coil over-current associated with the H-L transition, that fast rampdowns are preferred, the density drops with Ip, and that the H-L transition occurs at Ploss/Pthr,LH ~ 1.0-1.3 at n/nGr ~ 0.85. Flattop plasmas targeting ITER baseline parameters have been sustained for 20 ?E or 8-13 ?CR, but only reach H98 ~ 0.6 at n/nGr = 0.85, rising to 0.9 at n/nGr = 0.65.

C Kessel, et al

2013-05-07T23:59:59.000Z

402

Abrupt structural transitions involving functionally optimal networks  

E-Print Network (OSTI)

We show analytically that abrupt structural transitions can arise in functionally optimal networks, driven by small changes in the level of transport congestion. Our findings are based on an exactly solvable model system which mimics a variety of biological and social networks. Our results offer an explanation as to why such diverse sets of network structures arise in Nature (e.g. fungi) under essentially the same environmental conditions. As a by-product of this work, we introduce a novel renormalization scheme involving `cost motifs' which describes analytically the average shortest path across multiple-ring-and-hub networks.

Jarrett, T C; Fricker, M; Johnson, N F; Jarrett, Timothy C.; Ashton, Douglas J.; Fricker, Mark; Johnson, Neil F.

2005-01-01T23:59:59.000Z

403

Abrupt structural transitions involving functionally optimal networks  

E-Print Network (OSTI)

We show analytically that abrupt structural transitions can arise in functionally optimal networks, driven by small changes in the level of transport congestion. Our findings are based on an exactly solvable model system which mimics a variety of biological and social networks. Our results offer an explanation as to why such diverse sets of network structures arise in Nature (e.g. fungi) under essentially the same environmental conditions. As a by-product of this work, we introduce a novel renormalization scheme involving `cost motifs' which describes analytically the average shortest path across multiple-ring-and-hub networks.

Timothy C. Jarrett; Douglas J. Ashton; Mark Fricker; Neil F. Johnson

2005-08-31T23:59:59.000Z

404

Comparison and Analysis of Twist Pitch Length Test Methods for ITER Nb3Sn and NbTi Strands  

E-Print Network (OSTI)

A twisted multifilamentary structure is needed for Nb3Sn and NbTi strands to be used in the International Thermonuclear Experimental Reactor (ITER) magnets. As important parameters for the superconducting strands design and production, the twist pitch length and direction of strands must meet the requirements according to ITER Procurement Arrangement (PA) and this must be verified. The technical requirements are 15mm+/-2mm for twist pitch length and right hand twist for direction. The strand twist pitch and the twist direction can be measured on straight sections of strand, which is recognized by the repetition of filament bundles or by the angle of the filaments. Several test methods and results are described and compared in this paper. The accuracy, uncertainty and feasibility of different methods are analyzed and recommended measurement methods are proposed for ITER strands verification.

Fang Liu; Feng Long; Chao Chen; Bo Liu; Yu Wu; Huajun Liu

2013-05-08T23:59:59.000Z

405

Rate Adjustments and Public Involvement  

NLE Websites -- All DOE Office Websites (Extended Search)

Rate Adjustments and Public Involvement Documents Rate Adjustments and Public Involvement Documents CRSP Transmission 9/16/2013 WAPA-161 FRN, CRSP transmission and ancillary services rates extension Letter announcing two-year extension to CRSP transmission and ancillary services rates Letter announcing revised CRSP transmission rates for FY 2014 Accompanying calculation table for FY 2014 CRSP transmission rate letter Letter announcing revised CRSP transmission rates for FY 2013 Letter announcing revised CRSP transmission rates for FY 2012 Letter announcing revised CRSP transmission rates for FY 2011 Letter announcing revised CRSP transmission rates for FY 2010 SLCA/IP 9/16/2013 WAPA-161 FRN, SLCA/IP firm power rate extension Letter announcing two-year extension to SLCA/IP firm power rate SLCA/IP Tentative Rate Adjustment Schedule

406

RAMI Analysis for Designing and Optimizing Tokamak Cooling Water System (TCWS) for the ITER's Fusion Reactor  

SciTech Connect

U.S.-ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). TCWS is designed to provide cooling and baking for client systems that include the first wall/blanket, vacuum vessel, divertor, and neutral beam injector. Additional operations that support these primary functions include chemical control of water provided to client systems, draining and drying for maintenance, and leak detection/localization. TCWS interfaces with 27 systems including the secondary cooling system, which rejects this heat to the environment. TCWS transfers heat generated in the Tokamak during nominal pulsed operation - 850 MW at up to 150 C and 4.2 MPa water pressure. Impurities are diffused from in-vessel components and the vacuum vessel by water baking at 200-240 C at up to 4.4 MPa. TCWS is complex because it serves vital functions for four primary clients whose performance is critical to ITER's success and interfaces with more than 20 additional ITER systems. Conceptual design of this one-of-a-kind cooling system has been completed; however, several issues remain that must be resolved before moving to the next stage of the design process. The 2004 baseline design indicated cooling loops that have no fault tolerance for component failures. During plasma operation, each cooling loop relies on a single pump, a single pressurizer, and one heat exchanger. Consequently, failure of any of these would render TCWS inoperable, resulting in plasma shutdown. The application of reliability, availability, maintainability, and inspectability (RAMI) tools during the different stages of TCWS design is crucial for optimization purposes and for maintaining compliance with project requirements. RAMI analysis will indicate appropriate equipment redundancy that provides graceful degradation in the event of an equipment failure. This analysis helps demonstrate that using proven, commercially available equipment is better than using custom-designed equipment with no field experience and lowers specific costs while providing higher reliability. This paper presents a brief description of the TCWS conceptual design and the application of RAMI tools to optimize the design at different stages during the project.

Ferrada, Juan J [ORNL; Reiersen, Wayne T [ORNL

2011-01-01T23:59:59.000Z

407

Feasibility of the Direct Method to Solve the Anelastic Pressure Equation in Nonhydrostatic Two-Dimensional Mesoscale Models  

Science Conference Proceedings (OSTI)

For anelastic nonhydrostatic mesoscale models, the pressure has to be solved from the Poisson partial differential equation. This can be done in various ways. Here the usually neglected direct method is compared to widely used (iterative) ...

Antoon Meesters

1992-10-01T23:59:59.000Z

408

Initial acquisition performance of the multiple receive antenna assisted DS-UWB downlink using search space reduction and iterative code phase estimation  

Science Conference Proceedings (OSTI)

In this paper we propose and investigate an iterative code acquisition scheme assisted by both Search Space Reduction (SSR) and iterative Message Passing (MP), which was designed for the multiple receive antenna assisted Direct Sequence-Ultra WideBand ... Keywords: direct sequence-ultra wideBand (DS-UWB), initial acquisition, mean acquisition time (MAT), message passing (MP), search space reduction (SSR)

SeungHwan Won; Lajos Hanzo

2009-01-01T23:59:59.000Z

409

Experimental implementation of active force control and iterative learning technique to a two-link arm driven by penumatic artificial muscles  

Science Conference Proceedings (OSTI)

This paper highlights the practical viability and feasibility of an active force control (AFC) technique incorporating an iterative learning (IL) algorithm known as AFCAIL applied to a two-link planar arm actuated by a pair of pneumatic artificial muscles ... Keywords: active force control, hardware-in-the-loop simulation, iterative learning, pneumatic artificial muscle

M. Mailah; H. H. Mun; S. Kazi; H. Jahanabadi

2011-12-01T23:59:59.000Z

410

Coupling the Mixed Potential and Radiolysis Models for Used Fuel Degradation  

SciTech Connect

The primary purpose of this report is to describe the strategy for coupling three process level models to produce an integrated Used Fuel Degradation Model (FDM). The FDM, which is based on fundamental chemical and physical principals, provides direct calculation of radionuclide source terms for use in repository performance assessments. The G-value for H2O2 production (Gcond) to be used in the Mixed Potential Model (MPM) (H2O2 is the only radiolytic product presently included but others will be added as appropriate) needs to account for intermediate spur reactions. The effects of these intermediate reactions on [H2O2] are accounted for in the Radiolysis Model (RM). This report details methods for applying RM calculations that encompass the effects of these fast interactions on [H2O2] as the solution composition evolves during successive MPM iterations and then represent the steady-state [H2O2] in terms of an “effective instantaneous or conditional” generation value (Gcond). It is anticipated that the value of Gcond will change slowly as the reaction progresses through several iterations of the MPM as changes in the nature of fuel surface occur. The Gcond values will be calculated with the RM either after several iterations or when concentrations of key reactants reach threshold values determined from previous sensitivity runs. Sensitivity runs with RM indicate significant changes in G-value can occur over narrow composition ranges. The objective of the mixed potential model (MPM) is to calculate the used fuel degradation rates for a wide range of disposal environments to provide the source term radionuclide release rates for generic repository concepts. The fuel degradation rate is calculated for chemical and oxidative dissolution mechanisms using mixed potential theory to account for all relevant redox reactions at the fuel surface, including those involving oxidants produced by solution radiolysis and provided by the radiolysis model (RM). The RM calculates the concentration of species generated at any specific time and location from the surface of the fuel. Several options being considered for coupling the RM and MPM are described in the report. Different options have advantages and disadvantages based on the extent of coding that would be required and the ease of use of the final product.

Buck, Edgar C.; Jerden, James L.; Ebert, William L.; Wittman, Richard S.

2013-08-30T23:59:59.000Z

411

Iterative quantum state transfer along a chain of nuclear spin qubits  

E-Print Network (OSTI)

Transferring quantum information between two qubits is a basic requirement for many applications in quantum communication and quantum information processing. In the iterative quantum state transfer (IQST) proposed by D. Burgarth et al. [Phys. Rev. A 75, 062327 (2007)], this is achieved by a static spin chain and a sequence of gate operations applied only to the receiving end of the chain. The only requirement on the spin chain is that it transfers a finite part of the input amplitude to the end of the chain, where the gate operations accumulate the information. For an appropriate sequence of evolutions and gate operations, the fidelity of the transfer can asymptotically approach unity. We demonstrate the principle of operation of this transfer scheme by implementing it in a nuclear magnetic resonance quantum information processor.

Jingfu Zhang; Nageswaran Rajendran; Xinhua Peng; Dieter Suter

2007-06-03T23:59:59.000Z

412

Iterative equalization and decoding using reduced-state sequence estimation based soft-output algorithms  

E-Print Network (OSTI)

We study and analyze the performance of iterative equalization and decoding (IED) using an M-BCJR equalizer. We use bit error rate (BER), frame error rate simulations and extrinsic information transfer (EXIT) charts to study and compare the performances of M-BCJR and BCJR equalizers on precoded and non-precoded channels. Using EXIT charts, the achievable channel capacities with IED using the BCJR, M-BCJR and MMSE LE equalizers are also compared. We predict the BER performance of IED using the M-BCJR equalizer from EXIT charts and explain the discrepancy between the observed and predicted performances by showing that the extrinsic outputs of the $M$-BCJR algorithm are not true logarithmic-likelihood ratios (LLR's). We show that the true LLR's can be estimated if the conditional distributions of the extrinsic outputs are known and finally we design a practical estimator for computing the true LLR's from the extrinsic outputs of the M-BCJR equalizer.

Tamma, Raja Venkatesh

2005-05-01T23:59:59.000Z

413

Iterative method to compute the Fermat points and Fermat distances of multiquarks  

E-Print Network (OSTI)

The multiquark confining potential is proportional to the total distance of the fundamental strings linking the quarks and antiquarks. We address the computation of the total string distance an of the Fermat points where the different strings meet. For a meson (quark-antiquark system) the distance is trivially the quark-antiquark distance. For a baryon (three quark system) the problem was solved geometrically from the onset, by Fermat and by Torricelli. The geometrical solution can be determined just with a rule and a compass, but translation of the geometrical solution to an analytical expression is not as trivial. For tetraquarks, pentaquarks, hexaquarks, etc, the geometrical solution is much more complicated. Here we provide an iterative method, converging fast to the correct Fermat points and the total distances, relevant for the multiquark potentials. We also review briefly the geometrical methods leading to the Fermat points and to the total distances.

P. Bicudo; M. Cardoso

2008-12-03T23:59:59.000Z

414

Upgrade of the infrared camera diagnostics for the JET ITER-like wall divertor  

SciTech Connect

For the new ITER-like wall at JET, two new infrared diagnostics (KL9B, KL3B) have been installed. These diagnostics can operate between 3.5 and 5 {mu}m and up to sampling frequencies of {approx}20 kHz. KL9B and KL3B image the horizontal and vertical tiles of the divertor. The divertor tiles are tungsten coated carbon fiber composite except the central tile which is bulk tungsten and consists of lamella segments. The thermal emission between lamellae affects the surface temperature measurement and therefore KL9A has been upgraded to achieve a higher spatial resolution (by a factor of 2). A technical description of KL9A, KL9B, and KL3B and cross correlation with a near infrared camera and a two-color pyrometer is presented.

Balboa, I.; Arnoux, G.; Kinna, D.; Thomas, P. D. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Eich, T.; Sieglin, B.; Devaux, S.; Zeidner, W. [Max-Planck-IPP, EURATOM Association, D-85748 Garching (Germany); Morlock, C.; Kruezi, U.; Sergienko, G.; Rack, M. [Institut fuer Energie und Klimaforschung Plasmaphysik, Forschungszentrum Juelich GmbH, EURATOM Association FZJ, D-52425 Juelich (Germany); Collaboration: JET EFDA Contributors

2012-10-15T23:59:59.000Z

415

Progress toward a microsecond duration, repetitive, intense-ion beam for active spectroscopic measurements on ITER  

SciTech Connect

The authors describe the design of an intense, pulsed, repetitive, neutral beam based on magnetically insulated diode technology for injection into ITER for spectroscopic measurements of thermalizing alpha particle and thermal helium density profiles, ion temperature, plasma rotation, and low Z impurity concentrations in the confinement region. The beam is being developed to enhance low signal-to-noise ratios expected with conventional steady-state ion beams because of severe beam attenuation and intense bremstrahlung emission. A 5 GW (e.g., 100 keV, 50 kA) one-microsecond-duration beam would increase the signal by 10{sup 3} compared to a conventional 5 MW beam with signal-to-noise ratios comparable to those from a chopped conventional beam in one second.

Davis, H.A.; Bartsch, R.R.; Barnes, C.W. [and others

1996-06-01T23:59:59.000Z

416

Design of a mechanically actuated RF grounding system for the ITER ICRH antenna  

E-Print Network (OSTI)

In the ITER equatorial ports containing ICRH antennas, parasitic electrical resonances can be excited in the nominal 20 mm clearance gap between the port walls and the plug contained within it. RF calculations have established that these resonances can be effectively mitigated by a series of suitably located electrically conducting contacts between the port and plug. These contacts must allow installation and removal of the antenna but must also make reliable electrical contact during antenna operation. In addition, the contacts must be compliant enough to survive deflection of the port during seismic and disruption events without transmitting large forces to the vacuum vessel. The distance to be spanned is subject to significant uncertainty, due to the large manufacturing tolerances of the surrounding components, and this also must be considered during the design process. This paper outlines progress made in the design of the grounding system, as well as detailing a number of concepts which have been investi...

Hancock, D; Beaumont, B; Dumortier, P; Durodie, F; Kyrytsya, V; Louche, F; McKinley, R; Nicholls, K

2013-01-01T23:59:59.000Z

417

Benchmarking MELCOR 1.8.2 for ITER Against Recent EVITA Results  

Science Conference Proceedings (OSTI)

A version of MELCOR 1.8.2 modified for use in ITER Preliminary Safety Report analyses was validated against recent data from the EVITA facility located in Cadarache, France. EVITA Test Series 7 was used for this study to verify MELCOR’s ability to predict the pressures, temperatures, cryoplate ice mass, and vaccum vessel (VV) condensate mass for test conditions in EVITA that include injections of steam, nitrogen, and water in to the EVITA VV after the walls had been heated to 165 ºC and the cryoplate had been cooled to -193 ºC. In general, the ability of MELCOR to predict the VV pressure and wall temperatures for the steam only and water only injection tests was very good. Predicted ice layer masses where larger than reported for the EVITA cryoplate, in particular for the steam only injection tests (~40% too high), and the predicted condensate masses were less that measured in EVITA. Both of these descrpancies can be explained by ice porosity. The modified MELCOR 1.8.2 over predicts the EVITA VV pressure for the co-injection tests (e.g., steam plus nitrogen, or water plus nitrogen injections) by almost a factor of two. Based on parametric runs that where made by increasing the predicted cryoplate condensation rate, it is believed that this pressure over prediction is a result of an under predicted cryoplate condensation rate. The particulars of this study are documented in this report as well as conclusions about the impact this study has regarding the use of this verions of MELCOR for consequence analyses for ITER safety reports.

Merrill, Brad J

2007-11-01T23:59:59.000Z

418

Comparison of Lanczos and subspace iterations for hyperspherical reaction path calculations  

Science Conference Proceedings (OSTI)

In an accurate treatment of 3-dimensional reactive scattering using Adiabatically-adjusting, Principal axes Hyperspherical (APH) coordinates, we obtain a 2-dimensional Schr/umlt o/dinger equation defined on the surface of a hypersphere. The surface Hamiltonian, which depends parametrically on the sector hyperradius /rho//sub h/, must be diagonalized for many (100/endash/200) values of /rho//sub h/. The surface (eigen)functions are expanded in a finite element basis, where a non-uniform finite element mesh is allowed to adjust for each /rho//sub h/. Projection of the finite element basis onto the surface Hamiltonian yields a generalized eigenvalue problem. Typically of the lowest 50/endash/100 eigenvalues and eigenfunctions are required at each /rho//sub h/. Since the calculation of the surface functions is currently the expensive step for our reactive scattering procedure, it is necessary to calculate these functions as efficiently as possible. In this paper, we use both the subspace iteration and block Lanczos (with selective orthogonalization) methods to calculate the surface functions. Using both solution methods, we diagonalize the finite element matrices (of order = 1729 and of half bandwidth = 109) constructed for the LiH + F in equilibrium Li + HF system. CPU timings for both methods are examined as a function of the number of converged eigenvalues. Since we can generate a good initial subspace form the eigenvectors calculated at the previous value of /rho//sub h/, we find that the subspace iteration is competitive with the block Lanczos method when many (90) eigenvalues are calculated. 20 refs., 6 figs., 1 tab.

Kress, J.D.; Parker, G.A.; Pack, R.T.; Archer, B.J.

1988-01-01T23:59:59.000Z

419

Development of a mirror-based endoscope for divertor spectroscopy on JET with the new ITER-like wall (invited)  

Science Conference Proceedings (OSTI)

A new endoscope with optimised divertor view has been developed in order to survey and monitor the emission of specific impurities such as tungsten and the remaining carbon as well as beryllium in the tungsten divertor of JET after the implementation of the ITER-like wall in 2011. The endoscope is a prototype for testing an ITER relevant design concept based on reflective optics only. It may be subject to high neutron fluxes as expected in ITER. The operating wavelength range, from 390 nm to 2500 nm, allows the measurements of the emission of all expected impurities (W I, Be II, C I, C II, C III) with high optical transmittance ({>=}30% in the designed wavelength range) as well as high spatial resolution that is {ITER relevant shutter system based on pneumatic techniques has been developed and integrated into the endoscope head. The endoscope is equipped with four digital CCD cameras, each combined with two filter wheels for narrow band interference and neutral density filters. Additionally, two protection cameras in the {lambda} > 0.95 {mu}m range have been integrated in the optical design for the real time wall protection during the plasma operation of JET.

Huber, A.; Brezinsek, S.; Mertens, Ph.; Schweer, B.; Sergienko, G.; Terra, A.; Clever, M.; Lambertz, H. T.; Samm, U. [Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich, EURATOM Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Arnoux, G.; Balshaw, N.; Edlingdon, T.; Farthing, J.; Matthews, G. F.; Riccardo, V.; Sanders, S.; Stamp, M.; Williams, J.; Zastrow, K. D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Egner, S. [Kayser-Threde GmbH, D-81379 Munich (Germany); and others

2012-10-15T23:59:59.000Z

420

Iterative Joint and Interference Nulling/ Cancellation Decoding Algorithms for Multi-Group Space Time Trellis Coded Systems  

E-Print Network (OSTI)

Iterative Joint and Interference Nulling/ Cancellation Decoding Algorithms for Multi-Group Space will focus on joint detection and interference nulling/ cancellation algorithms. Key Words: Multi-Group STTCs can be classified under two categories. The first is based on joint detection/ decoding. We started

Al-Ghadhban, Samir

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421

White Paper for Developing Electromagnetic Particle Injector system for ITER on NSTX-U University of Washington (19 July 2012)  

E-Print Network (OSTI)

White Paper for Developing Electromagnetic Particle Injector system for ITER on NSTX-U University of Washington (19 July 2012) 1/2 White Paper@aa.washington.edu This white paper describes our plans for developing a new system for safely

422

An iterative algorithm to produce a positive definite correlation matrix from an approximate correlation matrix (with a program user's guide)  

Science Conference Proceedings (OSTI)

This report contains an explanation of an algorithm that, when executed, will operate on any symmetric approximate correlation matrix by iteratively adjusting the eigenvalues of this matrix. The objective of this algorithm is to produce a valid, positive definite, correlation matrix. Also a description of a program (called POSDEF) which implements the algorithm is given.

Iman, R.L.; Davenport, J.M.

1982-06-01T23:59:59.000Z

423

The ITER VIS/IR wide angle viewing system: Challenges and on-going R and D  

SciTech Connect

The ITER tokamak is the next generation fusion device which will allow studying burning plasma obtained by a Deuterium-Tritium (D-T) fusion reaction during hundreds of seconds. ITER vacuum vessel real-time protection will be mandatory during plasma operation to avoid water leaks and critical plasma facing components degradation. The protection system will be based on a wide angle viewing system (WAVS) composed with 18 visible (VIS) and 18 infrared (IR) cameras covering 80 % of the vacuum vessel which will be one of the major imaging systems of ITER. Compared to protection systems routinely used on current tokamaks and based on imaging (VIS and/or IR), new constraints must be taken into account because of their influence on the system performance: the harsh environment (high neutron flux) and the metallic plasma facing components (both first wall and divertor). In this new demanding context, we have achieved three mandatory R and D studies starting from the understanding of the source of signals by using realistic photonic simulation up to real-time processing strategy taken into account first order optical design constraints to define what type of performance could be reached for ITER vacuum vessel protection. (authors)

Travere, J. M.; Aumeunier, M. H.; Joanny, M.; Jouve, M.; Martin, V.; Moncada, V.; Salasca, S. [CEA DSM, IRFM, F-13018 Saint Paul-Lez-Durance (France); Marot, L. [Univ. of Basel, Dept. of Physics, CH-4056 Basel (Switzerland); Chabaud, D. [OPTIS, ZE de la Farlede, F-83078 Toulon Cedex 9 (France); Ferme, J. J. [SESO, Pole d'Activite d'Aix en Provence, 305 Rue Louis Armand, F-13792 Aix en Provence Cedex 3 (France); Bremond, F.; Thonnat, M. [INRIA, 2004 route des Lucioles, F-06902 Sophia Antipolis Cedex (France)

2011-07-01T23:59:59.000Z

424

Models  

E-Print Network (OSTI)

• A very typical statistical/econometric model assumes something like yt ? i.i.d. f (y, x, ?) (1) where f (·) is a parametric family known up to parameters ?. • Parameter estimation: maximum likelihood ˆ?n = arg max ? ln f (Yt, Xt, ?) (2) t • What if the basic model assumptions of (1) are violated? The parametric family may not contain the true model f0(x, y) that generated the data; or the data may not be i.i.d.; etc. Misspecified

Stas Kolenikov; U Of Missouri; U Of Missouri

2007-01-01T23:59:59.000Z

425

Methodology to evaluate the performance of simulation models for alternative compiler and operating system configurations  

Science Conference Proceedings (OSTI)

Simulation modelers increasingly require greater flexibility for model implementation on diverse operating systems, and they demand high computational speed for efficient iterative simulations. Additionally, model users may differ in preference for proprietary ... Keywords: Crop model, G95, Gfortran, Linux, Open source, Windows

K. R. Thorp; J. W. White; C. H. Porter; G. Hoogenboom; G. S. Nearing; A. N. French

2012-02-01T23:59:59.000Z

426

Recent developments in stochastic modeling and upscaling of hydrologic properties in tuff  

Science Conference Proceedings (OSTI)

A set of detailed geostatistical simulations of porosity has been produced for a layered stratigraphic sequence of welded and nonwelded volcanic tuffs at Yucca Mountain, Nevada. The simulations are produced using a composite. model of spatial continuity and they are highly conditioned to abundant drill hole (core) information. A set of derivative simulations of saturated hydraulic conductivity has been produced, in the absence of conditioning data, using a cross-variable relationship developed from similar data elsewhere. The detailed simulations reproduce both the major stratigraphic units and finer scale layering indicated by the drill hole data. These simulations have been scaled up several order of magnitude to represent block-scale effective hydrologic properties suitable for use in numerical modeling of groundwater flow and transport. The upscaling process involves the reformulation of a previously reported method that iteratively adapts an initial arbitrary grid to ``homogenize`` the detailed hydraulic properties contained within the adjusted cell limits and to minimize the size of cell in highly heterogeneous regions. Although the computation of the block-effective property involves simple numerical averaging, the blocks over which these averages are computed are relatively homogeneous, which reduces the numerical difficulties involved in averaging non-additive properties, such as permeability. The entire process of simulation and upscaling is rapid and computationally efficient compared with alterative techniques. It is thus suitable for the Monte Carlo evaluation of the uncertainty in site characterization as it affects the results of groundwater flow and transport calculations.

Rautman, C.A. [Sandia National Labs., Albuquerque, NM (United States); Robey, T.H. [Spectra Research Inst., Albuquerque, NM (United States)

1992-12-31T23:59:59.000Z

427

A New, Iterative, Synchronous-Response Algorithm for Analyzing the Morton Effect  

E-Print Network (OSTI)

The present work proposes a new computational algorithm for analyzing Morton Effect using a Successive Iterative Synchronous Response Algorithm (SISRA). Previous studies on the Morton Effect were based on Eigen or Nyquist analysis for stability studies and predicted only an onset speed of instability. The outcome of SISRA is the convergence of response to a steady state orbit in a finite number of iterations. A progressive increase in the response with increasing running speed indicates the former instability. SISRA predicts both the synchronous response for the speed range of concern plus the speed where the response becomes divergent. SISRA is implemented in a Timochenko-beam-based finite-element rotordynamics software suite. SISRA analyzes the Morton Effect as a synchronous response problem with excitations from: (1) mechanical imbalance, (2) induced thermal bent shaft moments, and (3) mechanical imbalance that is induced by thermal bow. A general elliptical orbit can be decomposed into the sum of forward and backward circular orbits. As input, SISRA requires that, at a specified speed, equilibrium position, and orbit: (1) the predicted maximum differential temperature, and (2) the angle between hot spot (position of maximum temperature) and position of minimum film thickness. Two examples from the published literature are considered. SISRA predicted higher vibration levels, even before the motion diverges due to Morton Effect. In some cases, the synchronous response of the system due to Morton Effect is orders of magnitude greater than the response due only to mechanical imbalance. The combined effects of: (1) mechanical imbalance with induced thermal bent shaft moments, and (2) mechanical imbalance with thermally induced mechanical imbalance are also studied. The impact of induced thermal bent shaft moments is found to be greater than the mechanical imbalance induced by thermal bow. A parametric investigation on the impact of the changes of (1) bearing length to diameter ratio, (2) reduced viscosity of the lubricant, (3) bearing radial clearance to radius ratio and (4) overhung mass magnitude is performed to consider their respective impacts on synchronous response. Based on the available input data and the cases considered, reducing viscosity and reducing the overhung mass are found to be the best remedies to alleviate problems arising from the Morton Effect.

Saha, Rohit

2010-12-01T23:59:59.000Z

428

Safety Issues and Approach to Meet the Safety Requirements in Tokamak Cooling Water System of ITER  

Science Conference Proceedings (OSTI)

The ITER (Latin for 'the way') tokamak cooling water system (TCWS) consists of several separate systems to cool the major ITER components - the divertor/limiter, the first wall blanket, the neutral beam injector and the vacuum vessel. The ex-vessel part of the TCWS systems provides a confinement function for tritium and activated corrosion products in the cooling water. The Vacuum Vessel System also has a functional safety requirement regarding the residual heat removal from in-vessel components. A preliminary hazards assessment (PHA) was performed for a better understanding of the hazards, initiating events, and defense in depth mechanisms associated with the TCWS. The PHA was completed using the following steps. (1) Hazard Identification. Hazards associated with the TCWS were identified including radiological/chemical/electromagnetic hazards and physical hazards (e.g., high voltage, high pressure, high temperature, falling objects). (2) Hazard Categorization. Hazards identified in step (1) were categorized as to their potential for harm to the workers, the public, and/or the environment. (3) Hazard Evaluation. The design was examined to determine initiating events that might occur and that could expose the public, environment, or workers to the hazard. In addition the system was examined to identify barriers that prevent exposure. Finally, consequences to the public or workers were qualitatively assessed, should the initiating event occur and one or more of the barriers fail. Frequency of occurrence of the initiating event and subsequent barrier failure was qualitatively estimated. (4) Accident Analysis. A preliminary hazards analysis was performed on the conceptual design of the TCWS. As the design progresses, a detailed accident analysis will be performed in the form of a failure modes and effects analysis. The results of the PHA indicated that the principal hazards associated with the TCWS were those associated with radiation. These were low compared to hazards associated with nuclear fission reactors and were limited to potential exposure to the on-site workers if appropriate protective actions were not used. However, the risk to the general public off-site was found to be negligible even under worst case accident conditions.

Flanagan, George F [ORNL; Reyes, Susana [ITER Organization, Saint Paul Lez Durance, France; Chang, Keun Pack [ITER Organization, Saint Paul Lez Durance, France; Berry, Jan [ORNL; Kim, Seokho H [ORNL

2010-01-01T23:59:59.000Z

429

Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

ALE-AMR ALE-AMR code Wangyi Liu, John Bernard, Alex Friedman, Nathan Masters, Aaron Fisher, Velemir Mlaker, Alice Koniges, David Eder June 4, 2011 Abstract In this paper we describe an implementation of a single-fluid inter- face model in the ALE-AMR code to simulate surface tension effects. The model does not require explicit information on the physical state of the two phases. The only change to the existing fluid equations is an additional term in the stress tensor. We show results of applying the model to an expanding Al droplet surrounded by an Al vapor, where additional droplets are created. 1 Introduction The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The

430

Magnetostatic focal spot correction for x-ray tubes operating in strong magnetic fields using iterative optimization  

Science Conference Proceedings (OSTI)

Purpose: Combining x-ray fluoroscopy and MR imaging systems for guidance of interventional procedures has become more commonplace. By designing an x-ray tube that is immune to the magnetic fields outside of the MR bore, the two systems can be placed in close proximity to each other. A major obstacle to robust x-ray tube design is correcting for the effects of the magnetic fields on the x-ray tube focal spot. A potential solution is to design active shielding that locally cancels the magnetic fields near the focal spot. Methods: An iterative optimization algorithm is implemented to design resistive active shielding coils that will be placed outside the x-ray tube insert. The optimization procedure attempts to minimize the power consumption of the shielding coils while satisfying magnetic field homogeneity constraints. The algorithm is composed of a linear programming step and a nonlinear programming step that are interleaved with each other. The coil results are verified using a finite element space charge simulation of the electron beam inside the x-ray tube. To alleviate heating concerns an optimized coil solution is derived that includes a neodymium permanent magnet. Any demagnetization of the permanent magnet is calculated prior to solving for the optimized coils. The temperature dynamics of the coil solutions are calculated using a lumped parameter model, which is used to estimate operation times of the coils before temperature failure. Results: For a magnetic field strength of 88 mT, the algorithm solves for coils that consume 588 A/cm{sup 2}. This specific coil geometry can operate for 15 min continuously before reaching temperature failure. By including a neodymium magnet in the design the current density drops to 337 A/cm{sup 2}, which increases the operation time to 59 min. Space charge simulations verify that the coil designs are effective, but for oblique x-ray tube geometries there is still distortion of the focal spot shape along with deflections of approximately 3 mm in the radial and circumferential directions on the anode. Conclusions: Active shielding is an attractive solution for correcting the effects of magnetic fields on the x-ray focal spot. If extremely long fluoroscopic exposure times are required, longer operation times can be achieved by including a permanent magnet with the active shielding design.

Lillaney, Prasheel; Shin, Mihye; Conolly, Steven M.; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Bioengineering, University of California Berkeley, Berkeley, California 94720 (United States) and Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California 94720 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

2012-09-15T23:59:59.000Z

431

A high etendue spectrometer suitable for core charge eXchange recombination spectroscopy on ITER  

SciTech Connect

A feasibility study for the use of core charge exchange recombination spectroscopy on ITER has shown that accurate measurements on the helium ash require a spectrometer with a high etendue of 1mm{sup 2}sr to comply with the measurement requirements [S. Tugarinov et al., Rev. Sci. Instrum. 74, 2075 (2003)]. To this purpose such an instrument has been developed consisting of three separate wavelength channels (to measure simultaneously He/Be, C/Ne, and H/D/T together with the Doppler shifted direct emission of the diagnostic neutral beam, the beam emission (BES) signal), combining high dispersion (0.02 nm/pixel), sufficient resolution (0.2 nm), high efficiency (55%), and extended wavelength range (14 nm) at high etendue. The combined measurement of the BES along the same sightline within a third wavelength range provides the possibility for in situ calibration of the charge eXchange recombination spectroscopy signals. In addition, the option is included to use the same instrument for measurements of the fast fluctuations of the beam emission intensity up to 2 MHz, with the aim to study MHD activity.

Jaspers, R. J. E.; Scheffer, M. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, Eindhoven (Netherlands); Kappatou, A. [FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein (Netherlands); Valk, N. C. J. van der; Durkut, M.; Snijders, B. [TNO Science and Industry, P.O. Box 155, 2600 AD Delft (Netherlands); Marchuk, O.; Biel, W. [Institut fuer Energie und Klimaforschung-IEK-4 Forschungszentrum, Juelich GmbH, 52425 Juelich (Germany); Pokol, G. I. [Institute of Nuclear Techniques, Budapest University of Technology and Economics, EURATOM Association, P. O. Box 91, H-1521 Budapest (Hungary); Erdei, G. [Department of Atomic Physics, Budapest University of Technology and Economics, EURATOM Association, P. O. Box 91, H-1521 Budapest (Hungary); Zoletnik, S.; Dunai, D. [WIGNER RCP, RMKI, EURATOM Association, P. O. Box 91, H-1521 Budapest (Hungary)

2012-10-15T23:59:59.000Z

432

Development of iteration strategies for a practical implementation of a higher order transverse leakage approximation  

Science Conference Proceedings (OSTI)

Transverse integrated nodal diffusion methods currently represent the standard in full core neutronic simulation. The primary shortcoming in this approach is the utilization of the quadratic transverse leakage approximation. This approach, although proven to work well for typical LWR problems, is not consistent with the formulation of nodal methods and can cause accuracy and convergence problems. In previous work, an improved, consistent quadratic leakage approximation was formulated, which derived from the class of higher order nodal methods developed some years ago. In this paper a number of iteration schemes are developed around this consistent quadratic leakage approximation which yield accurate node average results in much improved calculational times. The developed consistent leakage approximation is extended in this work via a number of numerical schemes, the most promising of which results from utilizing the consistent leakage approximation as a correction method to the standard quadratic leakage approximation. Numerical results are demonstrated on a set of benchmark problems, such as the 3D IAEA LWR and MOX C5 problems. (authors)

Prinsloo, R. H.; Tomasevic, D. I. [Necsa, PO Box 582, Pretoria, 0001 (South Africa)

2012-07-01T23:59:59.000Z

433

Design of Electron Cyclotron Heating and Current Drive System of ITER  

Science Conference Proceedings (OSTI)

Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH and CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mm{phi} corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH and CD system has also a start-up sub-system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start-up through the equatorial launcher. R and Ds of components for high power long pulse and mirror steering mechanism have been on-going in the parties to establish a reliable ITER ECH and CD system.

Kobayashi, N. [ITER, Cadarache (France); Bigelow, T.; Rasmussen, D. [ORNL, Oak Ridge (United States); Bonicelli, T.; Ramponi, G.; Saibene, G. [EFDA, Garching (Germany); Cirant, S. [ENEA-CNR, Milan (Italy); Denisov, G. [IAP, Nizhny Novgorod (Russian Federation); Heidinger, R.; Piosczyk, B. [FZK, Karlsruhe (Germany); Henderson, M.; Hogge, J.-P.; Thumm, M.; Tran, M. Q. [CRPP, Lausanne (Switzerland); Rao, S. L. [IPR, Bhat (India); Sakamoto, K.; Takahashi, K. [JAEA, Naka (Japan); Temkin, R. J. [MIT PSFC, Cambridge (United States); Verhoeven, A. G. A. [FOM IPP, Rijnhuizen (Netherlands); Zohm, H. [MPI IPP, Garching (Germany)

2007-09-28T23:59:59.000Z

434

Perturbative Study of Energetic Particle Redistribution by Alfven Eigenmodes in ITER  

SciTech Connect

The modification of particle distributions by magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles. Flattening of a distribution due to phase mixing in an island or due to portions of phase space becoming stochastic is a process extremely rapid on the time scale of an experiment. In this paper we examine the effect of toroidal Alfven eigenmodes (TAE) and reversed shear Alfven eigenmodes (RSAE) in ITER on alpha particle and injected beam distributions using theoretically predicted mode amplitudes. It is found that for the equilibrium of a hybrid scenario even at ten times the predicted saturation level the modes have negligible effect on these distributions. A strongly reversed shear (or advanced) scenario, having a spectrum of modes that are much more global, is somewhat more susceptible to induced loss due to mode resonance, with alpha particle losses of over one percent with predicted amplitudes and somewhat larger with the assistance of toroidal field ripple. The elevated q profile contributes to stronger TAE (RSAE) drive and more unstable modes. An analysis of the existing mode-particle resonances is carried out to determine which modes are responsible for the profile modification and induced loss. We find that losses are entirely due to resonance with the counter-moving and trapped particle populations, with co-moving passing particles participating in resonances only deep within the plasma and not leading to loss.

N.N. Gorelenkov and R.B. White

2012-10-29T23:59:59.000Z

435

Phase diagram of Symmetric Iterated Prisoner's Dilemma of Two-Companies with Partial Imitation Rule  

E-Print Network (OSTI)

The problem of two companies of agents with one-step memory playing game is investigated in the context of the Iterated Prisoner's Dilemma under the partial imitation rule, where a player can imitate only those moves that he has observed in his games with his opponent. We limit our study to the special case where the players in the two groups enjoy the same conditions on a fully connected network, so that there are only two payoff matrices required: one for players playing games with members of the same company, and the other one for players playing games with members from a different company. We show that this symmetric case of two companies of players can be reduced to the one-company case with an effective payoff matrix, from which a phase diagram for the players using the two dominant strategies, Pavlov and Grim Trigger can be constructed. The phase diagram is computed by numerical integration of the approximate mean value equations. The results are in good agreement with simulations of the two-company mo...

Zhang, Liangsheng; Antony, Mathis; Szeto, K Y

2011-01-01T23:59:59.000Z

436

Iterative circular coinduction for CoCasl in Isabelle/HOL  

E-Print Network (OSTI)

Coalgebra has in recent years been recognized as the framework of choice for the treatment of reactive systems at an appropriate level of generality. Proofs about the reactive behavior of a coalgebraic system typically rely on the method of coinduction. In comparison to ‘traditional ’ coinduction, which has the disadvantage of requiring the invention of a bisimulation relation, the method of circular coinduction allows a higher degree of automation. As part of an effort to provide proof support for the algebraic-coalgebraic specification language CoCasl, we develop a new coinductive proof strategy which iteratively constructs a bisimulation relation, thus arriving at a new variant of circular coinduction. Based on this result, we design and implement tactics for the theorem prover Isabelle which allow for both automatic and semiautomatic coinductive proofs. The flexibility of this approach is demonstrated by means of examples of (semi-)automatic proofs of consequences of Co-Casl specifications, automatically translated into Isabelle theories by means of the Bremen heterogeneous Casl tool set Hets.

Daniel Hausmann; Till Mossakowski; Lutz Schröder

2005-01-01T23:59:59.000Z

437

High resolution fast wave reflectometry: JET design and implications for ITER  

Science Conference Proceedings (OSTI)

The measurement of the fuel mixture remains a very difficult task in thermonuclear plasmas, where the hydrogen isotopes are fully stripped and do not emit line radiation. On the other hand, direct determination of the ion species mix will be essential in the reactor to keep the mixture close to 50/50 and maximize the fusion output. In this paper, the design of fast wave reflectometry for JET is reviewed to show the potential of such a method in the perspective of ITER. The main design elements of the antenna and the detection system, based on vectorial measurements, are reported. The main challenges to such a diagnostic, mainly the intrinsic ion cyclotron emission from the plasma and the extensive use of ion cyclotron radiofrequencies as additional heating, are addressed in detail. The overall design indicates that the proposed system would be able to provide a measurement of the fuel ratio with spatial resolution in the range of few centimeters and temporal resolution in the range of 1 ms in the vast majority of JET scenarios.

Cupido, L.; Igreja, R.; Serra, F.; Manso, M. E. [EURATOM-IST Association, IPFN, IST, 1049-001 Lisboa (Portugal); Cardinali, A. [EURATOM-ENEA Association, Frascati I00044 (Italy); Murari, A. [JET-EFDA, Culham Science Centre, OX14 3DB. Abingdon (United Kingdom)

2008-10-15T23:59:59.000Z

438

Iterative optimizing quantization method for reconstructing three-dimensional images from a limited number of views  

DOE Patents (OSTI)

A three-dimensional image reconstruction method comprises treating the object of interest as a group of elements with a size that is determined by the resolution of the projection data, e.g., as determined by the size of each pixel. One of the projections is used as a reference projection. A fictitious object is arbitrarily defined that is constrained by such reference projection. The method modifies the known structure of the fictitious object by comparing and optimizing its four projections to those of the unknown structure of the real object and continues to iterate until the optimization is limited by the residual sum of background noise. The method is composed of several sub-processes that acquire four projections from the real data and the fictitious object: generate an arbitrary distribution to define the fictitious object, optimize the four projections, generate a new distribution for the fictitious object, and enhance the reconstructed image. The sub-process for the acquisition of the four projections from the input real data is simply the function of acquiring the four projections from the data of the transmitted intensity. The transmitted intensity represents the density distribution, that is, the distribution of absorption coefficients through the object.

Lee, Heung-Rae (Dublin, CA)

1997-01-01T23:59:59.000Z

439

Influence of the Edge Plasma Profile and Parameters on the Coupling of an ICRH Antenna. Application to ITER  

Science Conference Proceedings (OSTI)

The coupling to the fast wave of an ICRH antenna is principally determined by its distance to an optimum plasma density correlated to the cutoff one and by the density gradient between this optimum density and the bulk plasma. This explains the differences in coupling for the various heating and current drive phasings as predicted for different plasma edge profiles considered for ITER. For a given electron density edge profile the ion mix, the steady magnetic field and the frequency have also a significant effect on the coupling performances. These quantities affect the coupling mainly by influencing the position of the optimum density in the profile. A marked perturbation of the coupling leading to a large edge power deposition can occur when the Alfven resonance lies in the edge profile. The results are applied to different ICRF scenarios considered for ITER at full and half toroidal field.

Messiaen, A.; Koch, R.; Weynants, R. [LPP-ERM/KMS, EURATOM-Belgian State Association, Trilateral Euregio Cluster, Brussels (Belgium)

2011-12-23T23:59:59.000Z

440

High Dielectric Dummy Loads for ITER ICRH Antenna Laboratory Testing: Numerical Simulation of One Triplet Loading by Ferroelectric Ceramics  

SciTech Connect

Up to now, classical 'water' loads have been used for low power testing of ITER ICRH prototype or mock-up antennas . A fair description of the antenna frequency response is obtained excepted for the phasing (0 {pi} 0 {pi}). High dielectric loads are requested to improve the antenna response in the low frequency band. In view of laboratory testing, dummy loads are also required to have efficient wave spatial attenuation to avoid standing waves and to minimize load volume. In this paper, barium titanate ceramic powders mixed with water are shown to exhibit very attractive electromagnetic properties. Coupling performance of one triplet of the ITER ICRH antenna to such kind of loads is numerically investigated. The radiated wave attenuation into the load is also characterized. In spite of its frequency dispersion, 'barium titanate' loads are shown to allow the characterization of the full scale triplet frequency response on a scaled-down mock-up.

Champeaux, S.; Gouard, Ph. [CEA, DAM, DIF, F-91297 Arpajon (France); Bottollier-Curtet, H. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Dumortier, P.; Koch, R.; Kyrytsya, V.; Messiaen, A. [Laboratory of Plasma Physics, Association EURATOM-Belgian State, Trilateral Euregio Cluster, Royal Military Academy, B-1000 Brussels (Belgium)

2011-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "model involves iterative" from the National Library of EnergyBeta (NLEBeta).
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441

Iterated stretching and multiple beads-on-a-string phenomena in dilute solutions of highly-extensible flexible polymers  

E-Print Network (OSTI)

The dynamics of elastocapillary thinning in high molecular weight polymer solutions are re-examined using high-speed digital video microscopy. At long times, the evolution of the viscoelastic thread deviates from self-similar exponential decay and competition of elastic, capillary and inertial forces leads to the formation of a periodic array of beads connected by axially-uniform ligaments. This configuration is itself unstable and successive instabilities propagate from the necks connecting the beads and ligaments. This iterated process results in the development of multiple generations of beads in agreement with predictions of Chang et al. (1999), although experiments yield a different recursion relation between successive generations. At long times, finite extensibility truncates the iterated instability and axial translation of the bead arrays along the interconnecting threads leads to progressive coalescence before rupture of the fluid column.

Monica S. N. Oliveira; Gareth H. McKinley

2005-02-08T23:59:59.000Z

442

ITER: The International Thermonuclear Experimental Reactor and the nuclear weapons proliferation implications of thermonuclear-fusion energy  

E-Print Network (OSTI)

This paper contains two parts: (I) A list of "points" highlighting the strategic-political and military-technical reasons and implications of the very probable siting of ITER (the International Thermonuclear Experimental Reactor) in Japan, which should be confirmed sometimes in early 2004. (II) A technical analysis of the nuclear weapons proliferation implications of inertial- and magnetic-confinement fusion systems substantiating the technical points highlighted in the first part, and showing that while full access to the physics of thermonuclear weapons is the main implication of ICF, full access to large-scale tritium technology is the main proliferation impact of MCF. The conclusion of the paper is that siting ITER in a country such as Japan, which already has a large separated-plutonium stockpile, and an ambitious laser-driven ICF program (comparable in size and quality to those of the United States or France) will considerably increase its latent (or virtual) nuclear weapons proliferation status, and fo...

Gsponer, A; Gsponer, Andre; Hurni, Jean-Pierre

2004-01-01T23:59:59.000Z

443

Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method  

SciTech Connect

In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10{sup -5}-10{sup -6} spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 A, 0.3 A, and 0.4 A, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO{sub 2}, Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO{sub 2} glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.

Hong Xinguo; Chen Zhiqiang [Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794 (United States); Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, New Jersey 08544 (United States)

2012-06-15T23:59:59.000Z

444

An efficient load model for analyzing demand side management impacts  

SciTech Connect

The main objective of implementing Demand Side Management (DSM) in power systems is to change the utility's load shape--i.e. changes in the time pattern and magnitude of utility's load. Changing the load shape as a result of demand side activities could change the peak load, base load and/or energy demand. Those three variables have to be explicitly modeled into the load curve for properly representing the effects of demand side management. The impact of DSM will be manifested as higher or lower reliability levels. This paper presents an efficient technique to model the system load such that the impact of demand side management on the power system can be easily and accurately evaluated. The proposed technique to model the load duration curve will facilitate the representation of DSM impacts on loss-of-load probability, energy not served and energy consumption. This will provide an analytical method to study the impact of DSM on capacity requirements. So far iterative methods have been applied to study these impacts. The proposed analytical method results in a faster solution with higher accuracy. It takes only 18 seconds on an 80486 PC to solve each case study involving different peak and base loads, and energy use.

Rahman, S.; Rinaldy (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States))

1993-08-01T23:59:59.000Z

445

Towards the Modelling of the Second Solar Spectrum  

E-Print Network (OSTI)

This paper addresses the modelling issue of the linearly-polarized solar limb spectrum, which is due to scattering processes and it offers a rich diagnostic potential for exploring solar magnetic fields via the Hanle effect. However, this so-called second solar spectrum is full of mysterious spectral features, which cannot be understood with simplified polarization transfer theories, thus suggesting that the underlying scattering physics is more complex than previously thought. In this paper we argue that the physical understanding of the second solar spectrum requires the consideration of scattering processes in multilevel atomic models, taking fully into account the transfer of atomic polarization among all the levels involved. The consideration of lower-level atomic polarization leads to non-linear and non-local coupled sets of equations, even for the two-level model atom case considered in this paper. The unknowns of the problem are the irreducible tensor components of the atomic density matrix whose self-consistent values have first to be obtained to be able to calculate the emergent Stokes profiles. To solve numerically this non-LTE problem of the second kind we present some iterative methods that are very suitable for developing a general multilevel scattering polarization code. We demonstrate that there exists metastable-level atomic polarization in the solar chromosphere, which suggests that the solution to some recently-formulated "paradoxes" is to be found by carefully revising our current ideas about the chromospheric magnetic field.

J. Trujillo Bueno

2007-10-29T23:59:59.000Z

446

Work function measurements during plasma exposition at conditions relevant in negative ion sources for the ITER neutral beam injection  

SciTech Connect

Cesium seeded sources for surface generated negative hydrogen ions are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER. The stability and delivered current density depend highly on the work function during vacuum and plasma phases of the ion source. One of the most important quantities that affect the source performance is the work function. A modified photocurrent method was developed to measure the temporal behavior of the work function during and after cesium evaporation. The investigation of cesium exposed Mo and MoLa samples under ITER negative hydrogen ion based neutral beam injection relevant surface and plasma conditions showed the influence of impurities which result in a fast degradation when the plasma exposure or the cesium flux onto the sample is stopped. A minimum work function close to that of bulk cesium was obtained under the influence of the plasma exposition, while a significantly higher work function was observed under ITER-like vacuum conditions.

Gutser, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Wimmer, C. [Lst. f. Experimentelle Plasmaphysik, Universitaet Augsburg, 86135 Augsburg (Germany); Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Lst. f. Experimentelle Plasmaphysik, Universitaet Augsburg, 86135 Augsburg (Germany)

2011-02-15T23:59:59.000Z

447

ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems  

E-Print Network (OSTI)

This paper contains two parts: (I) A list of “points ” highlighting the strategic-political and militarytechnical reasons and implications of the very probable siting of ITER (the International Thermonuclear Experimental Reactor) in Japan, which should be confirmed sometimes in early 2004. (II) A technical analysis of the nuclear weapons proliferation implications of inertial- and magnetic-confinement fusion systems substantiating the technical points highlighted in the first part, and showing that while full access to the physics of thermonuclear weapons is the main implication of ICF, full access to large-scale tritium technology is the main proliferation impact of MCF. The conclusion of the paper is that siting ITER in a country such as Japan, which already has a large separated-plutonium stockpile, and an ambitious laser-driven ICF program (comparable in size and quality to those of the United States or France) will considerably increase its latent (or virtual) nuclear weapons proliferation status, and foster further nuclear proliferation throughout the world. The safety and environmental problems related to the operation of largescale fusion facilities such as ITER (which contain massive amounts of hazardous and/or radioactive materials such as tritium, lithium, and beryllium, as well as neutron-activated structural materials) are not addressed in this paper.

André Gsponer; Jean-pierre Hurni

2004-01-01T23:59:59.000Z

448

Comment on "Wall Forces Produced During ITER Disruptions" by H. R. Strauss, R. Paccagnella, and J. Breslau (PHYSICS OF PLASMAS 17, 082505 (2010)  

Science Conference Proceedings (OSTI)

The paper by H.R. Strauss presents numerical simulations, which pretend to describe the disruption instability in ITER device. The simulations were performed with numerical code M3D, described in Ref.[7] of the paper.

Leonid E. Zakharov

2010-10-20T23:59:59.000Z

449

Modeling complex contacts involving deformable objects for haptic interaction.  

E-Print Network (OSTI)

??Haptic interaction allows a human user to touch and feel objects in virtual or remote environments with the tactile feedback as if he/she is handling… (more)

Luo, Qi

450

Cyber Incidents Involving Control Systems  

Science Conference Proceedings (OSTI)

The Analysis Function of the US-CERT Control Systems Security Center (CSSC) at the Idaho National Laboratory (INL) has prepared this report to document cyber security incidents for use by the CSSC. The description and analysis of incidents reported herein support three CSSC tasks: establishing a business case; increasing security awareness and private and corporate participation related to enhanced cyber security of control systems; and providing informational material to support model development and prioritize activities for CSSC. The stated mission of CSSC is to reduce vulnerability of critical infrastructure to cyber attack on control systems. As stated in the Incident Management Tool Requirements (August 2005) ''Vulnerability reduction is promoted by risk analysis that tracks actual risk, emphasizes high risk, determines risk reduction as a function of countermeasures, tracks increase of risk due to external influence, and measures success of the vulnerability reduction program''. Process control and Supervisory Control and Data Acquisition (SCADA) systems, with their reliance on proprietary networks and hardware, have long been considered immune to the network attacks that have wreaked so much havoc on corporate information systems. New research indicates this confidence is misplaced--the move to open standards such as Ethernet, Transmission Control Protocol/Internet Protocol, and Web technologies is allowing hackers to take advantage of the control industry's unawareness. Much of the available information about cyber incidents represents a characterization as opposed to an analysis of events. The lack of good analyses reflects an overall weakness in reporting requirements as well as the fact that to date there have been very few serious cyber attacks on control systems. Most companies prefer not to share cyber attack incident data because of potential financial repercussions. Uniform reporting requirements will do much to make this information available to Department of Homeland Security (DHS) and others who require it. This report summarizes the rise in frequency of cyber attacks, describes the perpetrators, and identifies the means of attack. This type of analysis, when used in conjunction with vulnerability analyses, can be used to support a proactive approach to prevent cyber attacks. CSSC will use this document to evolve a standardized approach to incident reporting and analysis. This document will be updated as needed to record additional event analyses and insights regarding incident reporting. This report represents 120 cyber security incidents documented in a number of sources, including: the British Columbia Institute of Technology (BCIT) Industrial Security Incident Database, the 2003 CSI/FBI Computer Crime and Security Survey, the KEMA, Inc., Database, Lawrence Livermore National Laboratory, the Energy Incident Database, the INL Cyber Incident Database, and other open-source data. The National Memorial Institute for the Prevention of Terrorism (MIPT) database was also interrogated but, interestingly, failed to yield any cyber attack incidents. The results of this evaluation indicate that historical evidence provides insight into control system related incidents or failures; however, that the limited available information provides little support to future risk estimates. The documented case history shows that activity has increased significantly since 1988. The majority of incidents come from the Internet by way of opportunistic viruses, Trojans, and worms, but a surprisingly large number are directed acts of sabotage. A substantial number of confirmed, unconfirmed, and potential events that directly or potentially impact control systems worldwide are also identified. Twelve selected cyber incidents are presented at the end of this report as examples of the documented case studies (see Appendix B).

Robert J. Turk

2005-10-01T23:59:59.000Z

451

Response of model simulated weather parameters to round-off-errors on different systems  

Science Conference Proceedings (OSTI)

In this study, the weather forecasting model of the National Centre for Medium Range Weather Forecasting (NCMRWF) is used for examining the characteristics of round-off-errors on three different computer architectures - PARAM 10K, SUNFIRE 6800 and Dec ... Keywords: Floating-point arithmetic, General Circulation Model (GCM), Iterative process, Model simulation, Round-off-errors, Spectral method

S. Goel; S. K. Dash

2007-08-01T23:59:59.000Z

452

Computational and conditioning issues of a discrete model for cochlear sensorineural hypoacusia  

Science Conference Proceedings (OSTI)

The interest of inner ear research towards the cochlear simulation is due to the lack of imaging techniques for human noninvasive investigation. Unfortunately, in case of Sensorineural Hearing Loss (SHL), the majority of the models developed in the literature ... Keywords: Cochlear modeling, Conditioning, Integrodifferential models, Iterative methods

Daniele Bertaccini; Stefano Fanelli

2009-08-01T23:59:59.000Z

453

Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor  

Science Conference Proceedings (OSTI)

The central problem of temperature-emissivity separation is that we obtain N spectral measurements of radiance and need to find N + 1 unknowns (N emissivities and one temperature). To solve this problem in the presence of the atmosphere we need to find even more unknowns: N spectral transmissions {tau}{sub atmo}({lambda}) up-welling path radiances L{sub path}{up_arrow}({lambda}) and N down-welling path radiances L{sub path}{down_arrow}({lambda}). Fortunately there are radiative transfer codes such as MODTRAN 3 and FASCODE available to get good estimates of {tau}{sub atmo}({lambda}), L{sub path}{up_arrow}({lambda}) and L{sub path}{down_arrow}({lambda}) in the order of a few percent. With the growing use of hyperspectral imagers, e.g. AVIRIS in the visible and short-wave infrared there is hope of using such instruments in the mid-wave and thermal IR (TIR) some day. We believe that this will enable us to get around using the present temperature - emissivity separation (TES) algorithms using methods which take advantage of the many channels available in hyperspectral imagers. The first idea we had is to take advantage of the simple fact that a typical surface emissivity spectrum is rather smooth compared to spectral features introduced by the atmosphere. Thus iterative solution techniques can be devised which retrieve emissivity spectra {epsilon} based on spectral smoothness. To make the emissivities realistic, atmospheric parameters are varied using approximations, look-up tables derived from a radiative transfer code and spectral libraries. By varying the surface temperature over a small range a series of emissivity spectra are calculated. The one with the smoothest characteristic is chosen. The algorithm was tested on synthetic data using MODTRAN and the Salisbury emissivity database.

Borel, C.C.

1997-11-01T23:59:59.000Z

454

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector  

Science Conference Proceedings (OSTI)

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A/m{sup 2} (346 mA) where the 3 x 5 apertures were used. Measurement of the beam profile revealed that deflection of the H{sup -} ions was large and a part of the H{sup -} ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m{sup 2} (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A/m{sup 2}).

Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Dairaku, M.; Takemoto, J.; Tobari, H.; Tsuchida, K.; Yamanaka, H.; Watanabe, K.; Kojima, A.; Hanada, M.; Sakamoto, K.; Inoue, T. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

2012-02-15T23:59:59.000Z

455

Predictions of Alpha Heating in ITER L-mode and H-mode Plasmas  

Science Conference Proceedings (OSTI)

Predictions of alpha heating in L-mode and H-mode DT plasmas in ITER are generated using the PTRANSP code. The baseline toroidal field of 5.3 T, plasma current ramped to 15 MA and a flat electron density profile ramped to Greenwald fraction 0.85 are assumed. Various combinations of external heating by negative ion neutral beam injection, ion cyclotron resonance, and electron cyclotron resonance are assumed to start half-way up the density ramp. The time evolution of plasma temperatures and, for some cases, toroidal rotation are predicted assuming GLF23 and boundary parameters. Significant toroidal rotation and flow-shearing rates are predicted by GLF23 even in the L-mode phase with low boundary temperatures, and the alpha heating power is predicted to be significant if the power threshold for the transition to H-mode is higher than the planned total heating power. The alpha heating is predicted to be 8-76 MW in L-mode at full density. External heating mixes with higher beam injection power have higher alpha heating power. Alternatively if the toroidal rotation is predicted assuming that the ratio of the momentum to thermal ion energy conductivity is 0.5, the flow-shearing rate is predicted to have insignificant effects on the GLF23- predicted temperatures, and alpha heating is predicted to be 8-20 MW. In H-mode plasmas the alpha heating is predicted to depend sensitively on the assumed pedestal temperatures. Cases with fusion gain greater than 10 are predicted to have alpha heating greater than 80 MW.

R.V. Budny

2011-01-06T23:59:59.000Z

456

Critical Design Issues of Tokamak Cooling Water System of ITER's Fusion Reactor  

SciTech Connect

U.S. ITER is responsible for the design, engineering, and procurement of the Tokamak Cooling Water System (TCWS). The TCWS transfers heat generated in the Tokamak to cooling water during nominal pulsed operation 850 MW at up to 150 C and 4.2 MPa water pressure. This water contains radionuclides because impurities (e.g., tritium) diffuse from in-vessel components and the vacuum vessel by water baking at 200 240 C at up to 4.4MPa, and corrosion products become activated by neutron bombardment. The system is designated as safety important class (SIC) and will be fabricated to comply with the French Order concerning nuclear pressure equipment (December 2005) and the EU Pressure Equipment Directive using ASME Section VIII, Div 2 design codes. The complexity of the TCWS design and fabrication presents unique challenges. Conceptual design of this one-of-a-kind cooling system has been completed with several issues that need to be resolved to move to next stage of the design. Those issues include flow balancing between over hundreds of branch pipelines in parallel to supply cooling water to blankets, determination of optimum flow velocity while minimizing the potential for cavitation damage, design for freezing protection for cooling water flowing through cryostat (freezing) environment, requirements for high-energy piping design, and electromagnetic impact to piping and components. Although the TCWS consists of standard commercial components such as piping with valves and fittings, heat exchangers, and pumps, complex requirements present interesting design challenges. This paper presents a brief description of TCWS conceptual design and critical design issues that need to be resolved.

Kim, Seokho H [ORNL; Berry, Jan [ORNL

2011-01-01T23:59:59.000Z

457

Design considerations for neutron activation and neutron source strength monitors for ITER  

SciTech Connect

The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for time-integrated neutron activation and time-dependent neutron source strength monitors, both of which will be important parts of the integrated suite of neutron diagnostics for this purpose. The primary goals of the neutron activation system are: to maintain a robust relative measure of fusion energy production with stability and wide dynamic range; to enable an accurate absolute calibration of fusion power using neutronic techniques as successfully demonstrated on JET and TFTR; and to provide a flexible system for materials testing. The greatest difficulty is that the irradiation locations need to be close to plasma with a wide field of view. The routing of the pneumatic system is difficult because of minimum radius of curvature requirements and because of the careful need for containment of the tritium and activated air. The neutron source strength system needs to provide real-time source strength vs. time with {approximately}1 ms resolution and wide dynamic range in a robust and reliable manner with the capability to be absolutely calibrated by in-situ neutron sources as done on TFTR, JT-60U, and JET. In this paper a more detailed look at the expected neutron flux field around ITER is folded into a more complete design of the fission chamber system.

Barnes, C.W. [Los Alamos National Lab., NM (United States); Jassby, D.L.; LeMunyan, G.; Roquemore, A.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Walker, C. [ITER Joint Central Team, Garching (Germany)

1997-12-31T23:59:59.000Z

458

Effect of Twist Pitch in the Strands on the Saturation and Losses in the Nb3Sn Strands for the ITER TF CICC  

SciTech Connect

ITER TF coils will see a significant longitudinal magnetic field in the event of the plasma disruption. This abrupt change of magnetic fields results in the appearance of an additional electrical field in the strands. The mechanism of this electrical field is the induced currents that expel the flux from the strands. This effect was known since the late 1970's [1-3] and most of the details necessary for the analyses given in this report are presented in [4]. Let's assume for simplicity a zero transport current in the strand. When a longitudinal pulsed field is applied, the outer filaments will carry an induced current repelling the change of flux. The current density of this current is 'critical' in the simplification of Bean's critical state model, where superconducting transition is represented as j=j{sub c} at any non-zero electrical field and zero where the electrical field has not penetrated. In reality, since the current density is roughly logarithmic with the electrical field, E=E{sub c}*exp[(j-j{sub c})/jo], Bean's model is just a simplification, and current density is slightly nonuniform in the outer filament and more so for the interior strands. The inner portion of the filaments will carry a current of the opposite sign. Even in the Bean's model it is not uniform, but the assumption that it is uniform and less than critical simplifies mathematics significantly and does not deviate far from the real current density distribution. In certain circumstances, the average electrical field in the strands will be high enough to exceed the take-off electrical field averaged across the cross section. In this case, the multifilamentary strand will become unstable and will experience transition to the normal state. With zero transport current, it will eventually recover, of course. This phenomenon is analogous to the flux jump. If the strand carries a transport current, the situation becomes more complicated. If it goes unstable and the transport current is higher than the cryostability limit (by Stekly), or if there are enough losses to bring the temperature above the current sharing temperature taking into account limited heat capacity of the CICC, the strand will not recover, and the CICC will go normal. Conservatively, we will consider that if we find an instantaneous unstable situation, it is not acceptable. In presence of a transport current, the situation is sensitive to the direction of the strand twist, direction of the pulsed field and direction of the transport current. Recently, ITER decided to increase the twist pitch of the TF strands from 15 mm to 30 mm to improve the stability of the strands against the longitudinal field. In this report we will quantify the effects of this proposed change and perform a trade off study. The issue is that by increasing the twist pitch of the strands we not only increase the coupling losses in the transverse magnetic field, as expected in classical multifilamentary composite superconductors, but also increase the hysteresis losses in the strands with internal tin. In classical multifilamentary superconductors, twist pitch change should not cause an increase of the hysteresis losses in the transverse field. However the high Nb3Sn content internal tin strands develop transverse links, which couple the filaments into clusters. These links turn out to contribute a significant fraction to hysteresis losses [5]. If we project the results of [5] onto the ITER proposal to increase the twist pitch from 15 to 30 mm, we should expect the hysteresis losses to increase by a factor of two, which will likely disqualify strands with 30 mm twist pitch. This very strand twisted to 15 mm twist pitch would likely pass the ITER criteria. So, increasing the twist pitch has a very negative consequence and we need to make sure that it is absolutely necessary. Recently, A. Vostner (private communication) reported preliminary results on the losses in candidate TF strands. In agreement with what was reported in [5]; he found that TF strands with 15 mm twist pitch have hysteresis losses about half of wh

Martovetsky, N N

2007-12-06T23:59:59.000Z

459

FOIASI - Special Inquiry Review of Allegations Involving  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

FOIASI - Special Inquiry Review of Allegations Involving FOIASI - Special Inquiry Review of Allegations Involving PotentialMisconduct by a Senior Office of Environmental Management Official FOIASI - Special Inquiry Review of Allegations Involving PotentialMisconduct by a Senior Office of Environmental Management Official In September 2009, the Office of Inspector General (OIG) received multiple allegations concerning improprieties by a senior official with the Office of Environmental Management. The allegations involved potential violations of political activity restrictions, lack of impartiality in performing official duties, misuse of position, and other related misconduct. Specific allegations concerned: 1. Orchestrating a $9 million American Recovery and Reinvestment Act of 2009 (Recovery Act) payment to certain Historically

460

Agent-based Ecological Model Calibration - on the Edge of a New Approach  

E-Print Network (OSTI)

The purpose of this paper is to present a new approach to ecological model calibration -- an agent-based software. This agent works on three stages: 1- It builds a matrix that synthesizes the inter-variable relationships; 2- It analyses the steady-state sensitivity of different variables to different parameters; 3- It runs the model iteratively and measures model lack of fit, adequacy and reliability. Stage 3 continues until some convergence criteria are attained. At each iteration, the agent knows from stages 1 and 2, which parameters are most likely to produce the desired shift on predicted results.

Pereira, Antonio; Reis, Luis Paulo

2008-01-01T23:59:59.000Z

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461

U.S. technical report for the ITER blanket/shield: A. blanket: Topical report, July 1990--November 1990  

SciTech Connect

Three solid-breeder water-cooled blanket concepts have been developed for ITER based on a multilayer configuration. The primary difference among the concepts is in the fabricated form of breeder and multiplier. All the concepts have beryllium for neutron multiplication and solid-breeder temperature control. The blanket design does not use helium gaps or insulator material to control the solid breeder temperature. Lithium oxide (Li{sub 2}O) and lithium zirconate (Li{sub 2}ZrO{sub 3}) are the primary and the backup breeder materials, respectively. The lithium-6 enrichment is 95%. The use of high lithium-6 enrichment reduces the solid breeder volume required in the blanket and consequently the total tritium inventory in the solid breeder material. Also, it increases the blanket capability to accommodate power variation. The multilayer blanket configuration can accommodate up to a factor of two change in the neutron wall loading without violating the different design guidelines. The blanket material forms are sintered products and packed bed of small pebbles. The first concept has a sintered product material (blocks) for both the beryllium multiplier and the solid breeder. The second concept, the common ITER blanket, uses a packed bed breeder and beryllium blocks. The last concept is similar to the first except for the first and the last beryllium zones. Two small layers of beryllium pebbles are located behind the first wall and the back of the last beryllium zone to reduce the total inventory of the beryllium material and to improve the blanket performance. The design philosophy adopted for the blanket is to produce the necessary tritium required for the ITER operation and to operate at power reactor conditions as much as possible. Also, the reliability and the safety aspects of the blanket are enhanced by using low-pressure water coolant and the separation of the tritium purge flow from the coolant system by several barriers.

Not Available

1995-01-01T23:59:59.000Z

462

Stability of Iterative Decoding of Multi-Edge Type Doubly-Generalized LDPC Codes Over the BEC  

E-Print Network (OSTI)

Using the EXIT chart approach, a necessary and sufficient condition is developed for the local stability of iterative decoding of multi-edge type (MET) doubly-generalized low-density parity-check (D-GLDPC) code ensembles. In such code ensembles, the use of arbitrary linear block codes as component codes is combined with the further design of local Tanner graph connectivity through the use of multiple edge types. The stability condition for these code ensembles is shown to be succinctly described in terms of the value of the spectral radius of an appropriately defined polynomial matrix.

Paolini, Enrico; Chiani, Marco; Fossorier, Marc P C

2011-01-01T23:59:59.000Z

463

Modelling approaches  

Science Conference Proceedings (OSTI)

Understanding and mitigating risks and threats to critical infrastructures relies heavily on the ability to construct and validate models often involving physical systems or even human intervention. This, together with the wide range of scales from critical ...

Nils Kalstad Svendsen; Stephen D. Wolthusen

2012-01-01T23:59:59.000Z

464